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 A139386 #6 Mar 30 2012 17:35:01 %S A139386 1,5,5,37,37,187,187,821,821,821,821,13301,13301,109941,109941,522717, %T A139386 522717,522717,522717,1247282901,1247282901 %N A139386 First gap of length at least n in A007950, lower end. %C A139386 All terms of A007950 are odd, therefore all gaps in A007950 have odd length and a(2*k) = a(2*k+1) for k >= 1. %C A139386 a(22) > 10^11. - Donovan Johnson %e A139386 First few terms of A007950 are 1,3,5,9,11, ... . The first gap of length 1 is between 1 and 3, so a(1) = 1; the first gap of length 2 is between 5 and 9; it has length 3, so a(2) = a(3) = 5. %Y A139386 Cf. A007950, A138845, A138900, A139387. %K A139386 nonn,more %O A139386 1,2 %A A139386 _Klaus Brockhaus_, Apr 17 2008 %E A139386 a(20)-a(21) from _Donovan Johnson_, Dec 27 2010