Question: ..., 18, 54, 3, ...


Sample: ..., 1, 1716, 1, ...

Answer: A059025


Sample: ..., 175450, 139759600, 6837625106787, ...

Answer: A011784

Sample:

0, 1, 3, 6, 2, 7, 
⋮             13, 
⋮             20, 
23,           12, 
10, 22,  11,  21,

Answer: A005132


Keywords: Mathematics, the Online Encyclopedia of Integer Sequences


Solution:
  1. Look for the integer sequence in the question on the Online Encyclopedia of Integer Sequences.
  2. Find the sequence number.

Answer: A133058