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 A260251 #28 Oct 14 2019 17:39:44 %S A260251 24,26,39,41,78,80,82,84,86,112,113,125,127,130,132,137,186,188,197, %T A260251 199,201,203,205,207,209,211,213,215,217,219,221,223,224,236,238,240, %U A260251 242,244,246,310,312,314,316,318,320,322,324,326,328,330,332,334,336,338,353 %N A260251 Indices of terms in Recamán's sequence A005132 that do not appear for the first time. %C A260251 A064284(A005132(a(n))) > 1. %H A260251 Peter Kagey, <a href="/A260251/b260251.txt">Table of n, a(n) for n = 1..10000</a> %Y A260251 Cf. A005132, A064284. %K A260251 nonn %O A260251 1,1 %A A260251 _Gionata Neri_, Apr 08 2016