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 A139387 #6 Mar 30 2012 17:35:01 %S A139387 2,11,133,497,4963,34486,68978,14877929,6186632564,6186632564 %N A139387 First gap of length at least n in A007951, lower end. %C A139387 a(11) > 10^11. - Donovan Johnson %e A139387 First few terms of A007951 are 1,2,4,5,7,8,10,11,14,16, ... . The first gap of length 1 is between 2 and 4, so a(1) = 2; the first gap of length 2 is between 11 and 14, so a(2) = 11. %Y A139387 Cf. A007951, A138845, A138900, A139386. %K A139387 nonn,more %O A139387 1,1 %A A139387 _Klaus Brockhaus_, Apr 17 2008 %E A139387 a(8)-a(10) from _Donovan Johnson_, Dec 27 2010