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 A070828 #6 Jul 03 2025 18:52:07 %S A070828 1,1,2,5,9,12,18,27,31,43,53,58,70,73,76,99,115,123,118,148,156,186, %T A070828 208,212,251,252,265,309,298,312,342,395,396,397,454,472,508,562,561, %U A070828 570,610,612,654,663,686,752,727 %N A070828 Sum of prime factors of Catalan numbers A000108(n), n>=2, with n=0 and n=1 terms added. %C A070828 a(0) := 1=: a(2) for A000108(0)= 1 = A000108(1). Sometimes a(0)= 0 =a(1) is chosen instead. %Y A070828 Cf. A001414 (for natural numbers), A064725 (for Fibonacci), A070827 (for Lucas). %K A070828 nonn,easy %O A070828 0,3 %A A070828 _Wolfdieter Lang_, May 10 2002