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 A226363 #11 Jun 13 2013 00:19:17 %S A226363 6,20,30,306,1722,2862,11772,13572,28730,29756,40602,54056,219492, %T A226363 351056,463080,947702,1391220,1546292,2043470,7174362,7703400, %U A226363 11400752,15104882,19127502,20155610,113667582,172173762,314299712,475654290,555238532,558447792,562519806 %N A226363 Oblong numbers (A002378) whose sum of divisors is also an oblong number. %H A226363 Donovan Johnson, <a href="/A226363/b226363.txt">Table of n, a(n) for n = 1..200</a> %t A226363 oblongQ[n_] := IntegerQ[(-1 + Sqrt[1 + 4*n])/2]; s = Select[Range[24000], oblongQ[DivisorSigma[1, # (# + 1)]] &]; s * (s + 1) (* _T. D. Noe_, Jun 12 2013 *) %Y A226363 Cf. A000203, A002378, A083674. %K A226363 nonn %O A226363 1,1 %A A226363 _Alex Ratushnyak_, Jun 05 2013