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 A265897 #9 Dec 25 2015 21:04:18 %S A265897 0,1,3,8,11,14,17,20,23,30,37,41,52,56,60,64,68,72,76,89,93,97,106, %T A265897 110,119,128,132,137,146,155,164,169,178,183,197,202,216,221,226,231, %U A265897 260,265,270,275,280,285,290,295,300,331,336,341,346,351,367,372,377,393,398,403,414,419,435,440,451,456,467,472,483,494,499,510 %N A265897 Numbers n for which (2n+1)! / n! [= A000407(n)] is >= k! but < 2*k! for some k; positions of ones in A265891. %C A265897 a(0) = 0 is a special case in this sequence, thus the indexing starts from zero. %C A265897 Numbers n such that A000407(n) is in A265334. %H A265897 Antti Karttunen, <a href="/A265897/b265897.txt">Table of n, a(n) for n = 0..845</a> %Y A265897 Cf. A000407, A265891, A265334. %Y A265897 Cf. also A265898. %K A265897 nonn %O A265897 0,3 %A A265897 _Antti Karttunen_, Dec 24 2015