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 A174906 #4 Mar 30 2012 17:31:28
%S A174906 24,48,80,120,168,224,49,360,440,528,624,728,840,960,1088,1224,1368,
%T A174906 1520,1680,1848,2024,2208,242,2600,2808,3024,3248,3480,3720,3968,4224,
%U A174906 4488,4760,5040,5328,5624,5928,6240,6560,6888,7224,7568,7920,8280,8648
%N A174906 a(n) is the index of the first triangular number T_i exceeding T_n such that the product of T_i*T_n is a perfect square.
%C A174906 "You can find an infinite number of [different] triangular numbers such that when multipled together form a square number. For example, for every triangular number, T_n, there are an infinite number of other triangular numbers, T_m, such that T_n*T_m is a square. For example, T_2 * T_24 = 30^2."
%D A174906 Clifford A. Pickover, The Loom of God, Tapestries of Mathematics and Mysticism, Sterling, NY, 2009, page 33.
%t A174906 tri[n_] := n (n + 1)/2; f[n_] := Block[{k = n + 1, t = tri@n}, While[ !IntegerQ@ Sqrt[ t*tri@k], k++ ]; k]; Table[ f@n, {n, 2, 46}]
%Y A174906 Cf. A132596, A007654, A132584.
%K A174906 nonn
%O A174906 2,1
%A A174906 _Robert G. Wilson v_, Apr 01 2010