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 A121562 #8 Jan 08 2019 05:18:39 %S A121562 1,7,2,4,2,4,2,2,4,4,4,2,2,4,2,2,4,2,4,4,4,2,2,4,4,2,2,2,4,2,6,2,2,4, %T A121562 2,4,2,2,7,2,3,2,2,2,4,4,7,1,4,4,2,4,2,2,2,4,2,4,4,7,1,4,2,4,7,2,1,2, %U A121562 7,2,1,2,2,4,2,2,4,4,7,1,2,4,2,4,2,4,4,4,2,2,4,7,1,2,7,2,3,2,2,4,2,2,7,2,3 %N A121562 Lengths of runs of identical terms in A121561. %H A121562 Kerry Mitchell, <a href="/A121562/b121562.txt">Table of n, a(n) for n = 1..2500</a> %e A121562 a(2) = 7 because A121561 begins 0, 1, 1, 1, 1, 1, 1, 1 and the second block of identical terms is 7 ones. %Y A121562 Cf. A121561. %K A121562 easy,nonn %O A121562 1,2 %A A121562 _Kerry Mitchell_, Aug 07 2006 %E A121562 Name and example edited by _M. F. Hasler_, Jan 07 2019