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 A024870 #3 Mar 30 2012 18:56:00 %S A024870 2,0,0,2,3,4,5,2,3,4,5,6,9,11,13,5,6,7,10,12,14,16,18,20,22,11,13,15, %T A024870 17,19,21,23,25,29,32,35,38,20,22,24,26,28,32,35,38,41,44,47,50,53,56, %U A024870 31,35,38,41,44,47,50,53,56,59,62,65,70,74,78,82,50,53,56,59,62,65,68,71,76,80,84,88 %N A024870 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = A023531. %K A024870 nonn %O A024870 2,1 %A A024870 _Clark Kimberling_