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 A068143 #22 Jul 11 2024 14:35:39 %S A068143 36,45,210,300,378,630,780,990,1485,1540,2850,3240,3570,4095,4851, %T A068143 4950,5460,8778,9180,11781,15400,17955,19110,21528,25200,26565,26796, %U A068143 31878,33930,37128,37950,39060,40755,43956,52650,61425,61776,70125,79800,82215,97020 %N A068143 Triangular numbers which are products of triangular numbers larger than 1. %H A068143 Pontus von Brömssen, <a href="/A068143/b068143.txt">Table of n, a(n) for n = 1..3597</a> (all terms below 10^12). %e A068143 210 is a term as 210 = 21*10 both triangular numbers. %e A068143 300 is also a term since 300 = 3*10*10. %Y A068143 Cf. A000217 (triangular numbers), A374374. %Y A068143 Except the first term, row n=3 of A374370 and row n=2 of A374498. %Y A068143 A188630 is a subsequence (only 2 factors allowed). %K A068143 nonn %O A068143 1,1 %A A068143 _Amarnath Murthy_, Feb 23 2002 %E A068143 Corrected and extended by _Jon E. Schoenfield_, Jul 23 2006 %E A068143 a(38)-a(41) from _Pontus von Brömssen_, Jul 02 2024