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 A131545 #16 Mar 24 2019 08:07:48
%S A131545 4,23,32,215,1261,538,4797,17612,32311,375482,512959,1847532,8295710,
%T A131545 8885853,80798025
%N A131545 Least k such that 3^k has exactly n consecutive 8's in its decimal representation.
%C A131545 No more terms < 10^8. - _Bert Dobbelaere_, Mar 20 2019
%e A131545 a(3)=32 because 3^32 (i.e., 1853020188851841) is the smallest power of 3 to contain a run of 3 consecutive eights in its decimal form.
%t A131545 a = ""; Do[ a = StringJoin[a, "8"]; b = StringJoin[a, "8"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
%Y A131545 Cf. A195269, A131552, A131551, A131550, A131549, A131548, A131547, A131546, A131544.
%K A131545 more,nonn,base
%O A131545 1,1
%A A131545 _Shyam Sunder Gupta_, Aug 26 2007
%E A131545 a(11)-a(14) from _Lars Blomberg_, Feb 02 2013
%E A131545 a(15) from _Bert Dobbelaere_, Mar 20 2019