Professor lirpa loof gave me a number sequence.

He started to say "It's as easy...", but I stopped him because he only ever talks in clichés and I don't like them. So then he promised not to talk, but instead wrote down these numbers.

37,81 70 91, 20,86 45 32 8, 39,77 22 81, -86,15 92 52 6, 50,71 86 33 1, -3,53 54 40 6

Can you figure out the what the number sequence is that he gave me before he started talking and before he gave me the list of numbers?

Hint 1

from the way the numbers are written I think the professor may have spent some time at school in France or Germany

Hint 2

the number sequence that you are looking for is not infinite - you are looking for a finite sequence of numbers.

Hint 3

when you obtain the number sequence you might be tempted to use a well known and famous mathematical equation to replace the numbers in the sequence by a single different number.

Hint 4

There are three numbers in the sequence....

  • $\begingroup$ Please see edit to the question - I realized that what I wrote was ambiguous so I have tried to make it unambiguous. You are looking for a number sequence - and a different list of numbers is given as a clue. ........... If necessary hints will be added as time goes by... $\endgroup$ – tom Apr 1 '18 at 15:03
  • $\begingroup$ Note - Question has been edited to add hints $\endgroup$ – tom Apr 1 '18 at 17:37
  • $\begingroup$ Note - the Question has been edited to add another hint (Hint 2). The progress made by @Riley and Sentinel is good and useful. $\endgroup$ – tom Apr 2 '18 at 19:39
  • $\begingroup$ @xhienne - yes well spotted - sorry my mistake there - I have fixed it, you could have considered editing it yourself perhaps :-)...... maybe, even you looked at it, which meant you spotted that extra space. $\endgroup$ – tom Apr 2 '18 at 22:42
  • $\begingroup$ @Reinier 's contribution and the contribution of everyone else has meant that this puzzle is very nearly solved, but I have added another hint..... $\endgroup$ – tom Apr 3 '18 at 18:52

Another partial answer:

As Sentinel noticed, the sequence consists of GPS coordinates, we get the following three coordinates by replacing commas without spaces with points and removing other spaces:
37.817091, 20.8645328, corresponding to Planos, Greece
39.772281, -86.1592526, corresponding to Indianapolis, USA
50.7186331, -3.5354406, corresponding to Exeter, UK

We see that

the first letters of these cities spell out PIE.


we can abbreviate Indianapolis and Exeter to INDEX, so the sequence we are looking for is probably some kind of index. I do not know what to do with Planos yet.

EDIT (with final answer, as suggested by Peregrine Rook):

As rng_died noticed, Planos is correctly spelled “Πλάνος” (because it is in Greece) (Wikipedia reference), so the first letter is actually a Π (upper-case π, pi), and not a P.  So the starting letters are π, i and e. These are also all mathematical constants, and probably the sequence that professor Lipra gave you. The famous mathematical equation that is mentioned in hint 3 is Euler’s identity ($e^{\pi i} = -1$).

  • 1
    $\begingroup$ Good work here, +1. I'm afraid everything after Furthermore is not correct, sorry. -- In the first two parts of your answer (before Furthermore) you are 95 % or more correct, but just not quite 100% correct. There is a subtlety that you are missing that will really help solve the puzzle $\endgroup$ – tom Apr 3 '18 at 15:39
  • $\begingroup$ Great job well done, you got so close, as did others with PIE, the professor would have said "as easy as $\pi$ie" by the way, which would have completely given it away. I think I have to award the bounty to rng_died as he figured out the solution first, but as things stand my plan is to accept your answer as it has the clearest explanation of how the puzzle is solved. So green check marker will be on the way provided the software lets me do this.... $\endgroup$ – tom Apr 6 '18 at 17:45

Partial answer:

When the Professor started to say "It's as easy", he/she was most likely about to say "as pie". So I believe the correct answer has something to do with $\pi$. I still believe that there is a reason that some of the numbers given are separated by a comma, some by a space, and some by both a comma and a space, although I realize that that is not the only information. I just can't figure out how to piece this information together.

OLD ANSWER: The pattern to the sequence is

That there is no pattern, because this is an April Fool's puzzle, as evidenced by your Professor's name spelled backwards

  • 2
    $\begingroup$ Ok so you smoked out part of what is going on, but I am afraid this is not the correct answer. There is a number sequence to find and you have not found it, so +1 but not correct i'm afraid. $\endgroup$ – tom Apr 1 '18 at 14:26
  • 1
    $\begingroup$ rot13(Qvq V whfg trg qbhoyr-Ncevy sbbyrq?) $\endgroup$ – Riley Apr 1 '18 at 14:28
  • $\begingroup$ Maybe... but the point is that there is a genuine puzzle here and if necessary hints will be provided in time.. don't judge by first appearances.... $\endgroup$ – tom Apr 1 '18 at 14:29
  • $\begingroup$ New answer using rot13(pbzznf naq fcnprf) - sorry not the correct approach $\endgroup$ – tom Apr 1 '18 at 14:57
  • $\begingroup$ Please see edit to the question - I realized that what I wrote was a bit ambiguous so I have tried to clarify it. $\endgroup$ – tom Apr 1 '18 at 15:02

Partial answer

The French and Germans use comma for decimal point


That makes the numbers look like polar coordinates or GPS coords


The reference to PI could be suggesting the coordinates are circular or spherical

  • $\begingroup$ Good work +1 :-). $\endgroup$ – tom Apr 1 '18 at 23:42
  • $\begingroup$ hint - first two parts are good, but the polar/spherical coordinates part is incorrect $\endgroup$ – tom Apr 2 '18 at 19:30
  • $\begingroup$ question edited with another hint added $\endgroup$ – tom Apr 2 '18 at 19:40
  • $\begingroup$ @tom unfortunately I am stuck away from PC on a naff old mobile. I suspect I need a maps app for this $\endgroup$ – Sentinel Apr 2 '18 at 20:24
  • $\begingroup$ hhhhmmmmm that might help.... $\endgroup$ – tom Apr 3 '18 at 12:03

Finishing off of Reinier's answer:

Plainos is PI, Indianapolis is I, and Exeter is E.

So the sequence is pi, i, and e, which match hint 3 very well.

  • $\begingroup$ In what sense are you adding to Reinier’s answer? What are you adding to Reinier’s answer? What are you saying about hint 3? What final answer are you giving?  (And how did you jump from the first group of letters to the first pair of letters?) $\endgroup$ – Peregrine Rook Apr 6 '18 at 14:27
  • 1
    $\begingroup$ I think that what is meant is that (rot 13) Cynabf vf va Terrpr, fb gur svefg yrggre vf npghnyyl n cv, abg n c. (Gur fhogyrgl V jnf zvffvat). Gur snzbhf rdhngvba vf Rhyref vqragvgl (r^(cv*v) = -1). $\endgroup$ – Reinier Apr 6 '18 at 14:42
  • $\begingroup$ @Reinier OK, I believe that you’ve solved it. You should edit it into your answer; I believe that this person deserves very little credit, since they did nothing more than give you a hint as to the piece of the puzzle that you were missing. $\endgroup$ – Peregrine Rook Apr 6 '18 at 14:59
  • $\begingroup$ Great job, well done. - This looks like your first post to this SE and you have solved something that has lain unsolved for a few days here. I hope you don't mind a couple of comments. You solved the problem and realized the reference to hint 3, but in your answer you have not explained why, I guess because it is obvious to you. Generally in answers here people state the answer and then put in some explanation of why this answer is correct. Hope this makes sense and hope you don't mind the comments. $\endgroup$ – tom Apr 6 '18 at 17:37
  • $\begingroup$ So - You are awarded the bounty because you came in and finished off the puzzle and understood what was going on first ----- but I am going to accept a different answer (if the software will let me) as being the best explanation of the answer --- because although you were the first and understood it the accepted answer will be clearer for anyone trying to understand the puzzle... ---- I can't award the bounty yet due to timing restriction.... $\endgroup$ – tom Apr 6 '18 at 17:41

Adding to Riley's answer (with full awareness that it's probably a coincidence):

Interpreting the sequence 1,2,2,3,2,2,2,3,2,3,2,3 as morse where 1s are dots, 2s are dashes, and 3s are spaces, the sequence means "wott".

  • $\begingroup$ it is a coincidence as expected, sorry, but +1 for the nice answer. $\endgroup$ – tom Apr 1 '18 at 14:55
  • $\begingroup$ Note the question has been edited to add hints $\endgroup$ – tom Apr 1 '18 at 17:39

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