I've created a puzzle and dressed it up as a puzzle.

The following message has been intercepted. You suspect it begins with the words THE KEY TO THIS METHOD. Decipher the message and describe the cipher method.


2 Answers 2


Partial answer:

If we take A1Z26 of both the cipher and UJIPLGEBIXBMICVKUKSETJGYXMHRAIY, we get:

20|08|05|11|05|25|20|15|20|08|09|19|13|05|20|08|15|04 21|10|09|16|12|07|05|02|09|24|02|13|09|03|22|11|21|11

After the 6th column, for some entries our top number is greater than our bottom number, so we will add 26 if that is the case.

20|08|05|11|05|25|20|15|20|08|09|19|13|05|20|08|15|04 21|10|09|16|12|33|31|28|35|24|28|39|35|29|22|11|21|11

So now we make the completely arbitrary case to

always add 26 to out bottom number after the 16th row.

So we change into

20|08|05|11|05|25|20|15|20|08|09|19|13|05|20|08|15|04 21|10|09|16|12|33|31|28|35|24|28|39|35|29|48|37|47|37

If we

subtract the bottom number from the top number

we get:

1, 2, 4, 5, 7, 8, 11, 13, 15, 16, 19, 20, 22, 24, 28, 29, 32, 33

which is

sequence A022559 in the OEIS, or the sum of exponents in the prime-power factorization in n!.

  • $\begingroup$ This sequence is A022559 in OEIS. $\endgroup$
    – DanDan面
    Jul 11, 2023 at 6:10
  • $\begingroup$ Oh. Well. I'll just go ahead and accept this answer, then. If anyone wants extra credit, they can figure out how to discover the sequence without using OEIS. $\endgroup$ Jul 11, 2023 at 7:55


incrementally the key is bcefhilnpqtuwycdghkmoptvxadehin
Mainly found by trail and terror in a decoder enter image description here

enter image description here


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