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 A165893 #3 Mar 30 2012 17:27:05 %S A165893 0,1,3,11,30,40,122,130,1972 %N A165893 Numbers n with property that n(n+2)(n+4) is a triangular number. %C A165893 Abscissas of integral points on the elliptic curve: m^2 = 8*n^3 + 48*n^2 + 64*n + 1. %t A165893 TNQ[n_]:=IntegerQ[Sqrt[1+8n]];Select[Range[7500],TNQ[ #(#+2)(#+4)]&] %Y A165893 Cf. A001219 Triangular numbers of form a(a+1)(a+2), A165892 Triangular numbers of form a(a+2)(a+4). %K A165893 nonn,fini,full %O A165893 1,3 %A A165893 _Zak Seidov_, Sep 29 2009 %E A165893 fini, full keywords from _Max Alekseyev_, Oct 01 2009 %E A165893 Initial 0 added by _Zak Seidov_, Oct 04 2009 at the suggestion of Alexander R. Povolotsky.