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 A216669 #15 Jul 26 2015 14:41:14
%S A216669 2,5,14,20,39,52,74,102,134,158,208,259,284,361,409,488,538,634,678,
%T A216669 838,857,1006,1038,1270,1264,1495,1500,1776,1761,2084,2062,2443,2300,
%U A216669 2795,2680,3194,3076,3544,3403,4080,3804,4518,4282,5037,4673,5626,5127,6088
%N A216669 Total number of parts in all partitions of n into 2 sizes of parts (A002133).
%C A216669 Also column k=2 of A255768. - _Omar E. Pol_, Jul 26 2015
%H A216669 Alois P. Heinz, <a href="/A216669/b216669.txt">Table of n, a(n) for n = 3..1000</a>
%F A216669 a(n) = Sum_{k=2..n-1} k * A216665(n,k).
%t A216669 nn=40;ss=Sum[Sum[y^2 x^(i+j)/(1-y x^i)/(1-y x^j),{j,1,i-1}], {i,1,nn}]; CoefficientList[Series[D[ss,y]/.y->1,{x,0,nn}],x]
%Y A216669 Cf. A002133, A216665, A255768.
%K A216669 nonn
%O A216669 3,1
%A A216669 _Geoffrey Critzer_, Sep 13 2012