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 A109726 #8 Dec 08 2018 11:42:58
%S A109726 0,5,36,156,442,954,1854,3154,4998,7514,10784,14786,19932,26148,33448,
%T A109726 42340,52208,64322,77898,93116,110224,129978,151990,175224,201584,
%U A109726 231272,263500,298590,335856,376616,420984,469894,521740,577304,634990
%N A109726 Divide primes in groups with 2n elements and add together.
%C A109726 First difference of A322420.
%H A109726 Ray Chandler, <a href="/A109726/b109726.txt">Table of n, a(n) for n = 0..10000</a>
%F A109726 a(n) = A007504(n*(n+1)) - A007504(n*(n-1)).
%t A109726 f[n_] := Sum[Prime[k], {k, n}]; Table[f[n*(n + 1)] - f[n*(n - 1)], {n, 0, 34}]
%Y A109726 Cf. A007504, A109722-A109725, A322420.
%K A109726 easy,nonn
%O A109726 0,2
%A A109726 _Giovanni Teofilatto_, Aug 10 2005
%E A109726 Edited and extended by _Ray Chandler_, Aug 11 2005