My friend sent me this tricky puzzle...

Please explain the reason for the mistake in the number sequence - what is it trying to communicate?

8139, 8140, 8141, 5493, 8143, 8144



Although not a number sequence puzzle, there is a sequence of some kind, albeit brief, lodged in here that will reveal the intended answer if noticed. Pay close attention to the Knowledge tag.

The history tag is certainly valid for this puzzle.

  • 1
    $\begingroup$ Would [number-sequence] be appropriate here? $\endgroup$
    – bobble
    Feb 12, 2021 at 4:42
  • $\begingroup$ Not really no. . $\endgroup$ Feb 12, 2021 at 9:16
  • $\begingroup$ The last hint confirmed what i suspected, but can't seem to find the relationship between the numbers.. rot13(vs vg jrer avar vafgrnq bs rvtug va gur svefg ahzore v jbhyq'ir orra cerggl fher :C) Or maybe not on the right track? $\endgroup$ Feb 13, 2021 at 14:28
  • $\begingroup$ should the last hint be added as a tag? It does exist... $\endgroup$ Feb 14, 2021 at 22:26

6 Answers 6


It seems they all represent

years of the WW2 (except 5493)

But the mistake in this puzzle is actually

the third term, 8141, and not the fourth one (5493) which one might think. The term 8141 actually represents the years of world war one (1914-1918) but backwards. Likewise, 5493, represents the years of ww2 (1939-1945) but backwards. So all the entries except one represents the ww2.


I believe OP just wanted to disguise the fact that this was about the ww2 by changing the 9 to 8.


As stated by OP

The message it's trying to communicate is WW1 going to WW2

  • $\begingroup$ Not exactly but close enough! $\endgroup$ Feb 18, 2021 at 14:05
  • $\begingroup$ Basically the mistake is just that the numbers should to be ascending +1 each time and the number 5493 throws a spanner in the works since the number in its place should be 8142. $\endgroup$ Feb 18, 2021 at 14:10
  • $\begingroup$ It was to communicate the sucession of WW1 going to WW2. $\endgroup$ Feb 18, 2021 at 14:14
  • $\begingroup$ Aah, ok. I'll put that in my answer $\endgroup$ Feb 18, 2021 at 14:18

The only relation I could find:


The absolute value is decreasing linearly

and the 4th element could be

5415 or 9354

  • $\begingroup$ Nice find. However this does not reveal which number is incorrect, because according to it all numbers are correct. $\endgroup$
    – Anonymous
    Feb 12, 2021 at 14:42
  • $\begingroup$ Welcome to Puzzling, Mehrdad :) While this is a valiant mathematics-based effort I suspect the OP has a different, more non-numerical connection in mind, as there's a comment on the main post itself which suggests it isn't actually related to a number sequence, even though it appears to be that way. This would explain why it's tagged 'knowledge' and 'lateral-thinking' instead. Something sneaky and deceptive is more likely going on here - no idea what myself though! :) $\endgroup$
    – Stiv
    Feb 12, 2021 at 15:58
  • $\begingroup$ right, the correct answer might be completely different. $\endgroup$ Feb 12, 2021 at 16:00
  • $\begingroup$ Indeed, and presumably relating to something trivia-related that isn't immediately obvious but can be converted to numbers like these, e.g. pairs of countries' international dialling codes (just an example - I don't think it is dialling codes because I can't spot a pattern there). $\endgroup$
    – Stiv
    Feb 12, 2021 at 16:03
  • $\begingroup$ Sorry, not the answer I was aiming at. $\endgroup$ Feb 12, 2021 at 16:07

My guess is it is communicating:

Happy Chinese New Year!

We observe a series of incremental 4 digit numbers (except the incorrect one).
Given the tag/hint, perhaps they are


So we can swap digits to make them look like these:

1839, 1840, 1841, (5493), 1843, 1844

We observe the missing year is


Which seems to be

The date of the Chinese New Year 4539 (Water Tiger). Which is what we get if we flip both successive digits of the bizarre number: 54>45,93>39 -> 4539. Given the date this puzzle was posted (Chinese New Year), it implies the above match could be more than a coincidence.

  • $\begingroup$ Whilst that is a very nice attempt, that was not my intended solution, but you have definitely got the right idea nonetheless. $\endgroup$ Feb 13, 2021 at 14:55

They all start with two digits that add up to 9, so perhaps they should be replaced with numbers 19XX instead of 18XX ... in which case they're all the years of WWII from 1939 to 1944, except the final year of the war 1945 is missing and where did 1942 go? The 5493 should end with 42, and the 5 could mean there's an additional term 1945 missing from the sequence.

  • $\begingroup$ So very close!! $\endgroup$ Feb 15, 2021 at 13:18
  • $\begingroup$ @Flinty I think rot13((gur 5493 ercerfragf gur ortvaavat naq raq bs jj2 ohg vf jevggra onpxjneqf, V nyfb guvax (sbe gur fnzr ernfba) vg pbhyq or cbffvoyr gung gur ahzore 8141 vf gur ortvaavat naq raq bs jj1 (gurl'er cynprq arkg gb rnpu bgure). V qba'g unir n pyrne nafjre gb guvf chmmyr gubhtu.) $\endgroup$ Feb 18, 2021 at 9:56
  • $\begingroup$ Prime numbah please write your answer🙂!! $\endgroup$ Feb 18, 2021 at 10:56
  • $\begingroup$ @Smartest1here I could write a partial ofc, but I just don't got the whole picture. Still a few "why's" im trying to answer $\endgroup$ Feb 18, 2021 at 11:54
  • $\begingroup$ No I am saying you got it right. $\endgroup$ Feb 18, 2021 at 11:55

I think I've narrowed it down to a few possibilities.

It seems that the numbers represent years from 1839 to 1844 with the year 1842 missing. So I started looking at historic events that happened in those years. I found:
* US depression from 1839 to 1843
* Rebecca Riots from 1839 to 1843
* Antarctic expedition from 1839 to 1843


None of these contain the number 5493 or variants of it. So I don't have the right answer. Perhaps these possibilities are on the right track though and could help others.


The excess number is 8139.

Lets put the given numbers into two groups and write them backwards.

 9318       3945 

 0418       3418 

 1418       4418 

If we eliminate all the 18s and the unwanted number 9318, we have

 04     39, 45

 14     34


On April 14, 1912 the Titanic collided with an iceberg, which caused it to sink. The years 44, 34, 39, 45 Hitler was in power in Germany.

  • 2
    $\begingroup$ I don't understand why you would invoke these dates specifically. Also, wasn't Hitler in power in other years as well? This answer to me seems to be finding connections where they don't exist. $\endgroup$
    – bobble
    Feb 17, 2021 at 3:09
  • $\begingroup$ Hitler ruled for 13 years. The given numbers are 6, so several years are missing. As for the rest, it is just your opinion. $\endgroup$ Feb 17, 2021 at 3:32
  • $\begingroup$ I think to strengthen this answer you would need to provide some connection between the Titanic and Hitler... perhaps in the form of answering the question part "What is it trying to communicate?" $\endgroup$
    – Graylocke
    Feb 18, 2021 at 0:46
  • $\begingroup$ He is trying to communicate historical events. $\endgroup$ Feb 18, 2021 at 5:19
  • 1
    $\begingroup$ Why is the excess number 8139? And how do you eliminate the 18s? There seem to be a lot of steps that aren't justified. $\endgroup$
    – samm82
    Feb 18, 2021 at 6:17

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