This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A131617 #13 Jun 08 2025 01:13:35
%S A131617 0,1,2,3,4,5,6,7,9,11,14,15,16,17,18,19,20,23,25,29,31,41,44,52,58,81,
%T A131617 91
%N A131617 Numbers k such that the decimal expansion of 3^k contains no 5.
%C A131617 I conjecture that 91 is the last term.
%t A131617 Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[3^# ], 5] &]]
%o A131617 (Magma) [n: n in [0..1000] | not 5 in Intseq(3^n) ]; // _Vincenzo Librandi_, May 06 2015
%Y A131617 Cf. similar sequences listed in A131613.
%Y A131617 Cf. A007377.
%K A131617 base,fini,nonn
%O A131617 1,3
%A A131617 _Shyam Sunder Gupta_, Sep 01 2007
%E A131617 Initial 0 added and Mathematica code adapted by _Vincenzo Librandi_, May 06 2015