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 A217180 #13 Jun 14 2025 19:08:39
%S A217180 67,131,67,88,176,146,95,131,6,163,44,253,225,255,67,290,98,148,7,138,
%T A217180 179,255,174,131,163,158,31,239,8,60,67,242,160,170,176,32,316,327,9,
%U A217180 192,231,190,148,240,260,228,63,146,9,64,107,206,148,159,188,250,71
%N A217180 a(n) is the number of digits in the decimal representation of the smallest power of n that contains five consecutive identical digits.
%C A217180 Number of digits in n^k is equal to floor(1 + k*log_10(n)).
%H A217180 V. Raman, <a href="/A217180/b217180.txt">Table of n, a(n) for n = 2..10000</a>
%t A217180 Table[k = 1; While[d = IntegerDigits[n^k]; ! MemberQ[Partition[Differences[d], 4, 1], {0, 0, 0, 0}], k++]; Length[d], {n, 2, 100}] (* _T. D. Noe_, Oct 03 2012 *)
%t A217180 Table[IntegerLength[NestWhile[n #&,n,SequenceCount[IntegerDigits[#],{x_,x_,x_,x_,x_}]<1&]],{n,2,60}] (* _Harvey P. Dale_, Jun 14 2025 *)
%Y A217180 Cf. A217160, A217170.
%K A217180 nonn,base
%O A217180 2,1
%A A217180 _V. Raman_, Sep 27 2012