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 A215236 #10 Nov 25 2020 11:17:54
%S A215236 15,10,7,10,4,5,5,5,1,0,1,8,2,1,3,6,4,4,1,1,0,5,3,5,4,3,7,4,1,5,4,0,1,
%T A215236 1,2,6,1,3,1,4,2,3,0,2,1,1,2,2,1,6,3,2,5,0,3,3,1,3,1,2,1,2,2,1,0,1,2,
%U A215236 3,1,2,6,5,2,5,1,0,2,3,1,2,2,1,4,1,3,5,0
%N A215236 Greatest integer k such that n^i has no identical consecutive digits for i = 0..k.
%H A215236 T. D. Noe, <a href="/A215236/b215236.txt">Table of n, a(n) for n = 2..10000</a>
%F A215236 a(n) = A217157(n) - 1. - _Georg Fischer_, Nov 25 2020
%e A215236 a(2) = 15 because the powers of 2 are 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536 and only the 16th power has consecutive identical digits.
%t A215236 Table[k = 1; While[! MemberQ[Differences[IntegerDigits[n^k]], 0], k++]; k = k - 1, {n, 2, 100}]
%Y A215236 Cf. A216063 (highest power of n having different consecutive digits), A217157.
%K A215236 nonn,base
%O A215236 2,1
%A A215236 _T. D. Noe_, Sep 17 2012