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 A131616 #13 Jun 08 2025 01:13:32
%S A131616 0,1,2,3,4,5,6,7,10,11,12,13,15,18,23,32,35,42,55,104
%N A131616 Numbers k such that the decimal expansion of 3^k contains no 6.
%C A131616 I conjecture that 104 is the last term.
%t A131616 Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[3^# ], 6] &]]
%o A131616 (Magma) [n: n in [0..1000] | not 6 in Intseq(3^n) ]; // _Vincenzo Librandi_, May 06 2015
%Y A131616 Cf. similar sequences listed in A131613.
%Y A131616 Cf. A007377.
%K A131616 base,fini,nonn
%O A131616 1,3
%A A131616 _Shyam Sunder Gupta_, Sep 01 2007
%E A131616 Initial 0 added and Mathematica code adapted by _Vincenzo Librandi_, May 06 2015