A068143 - OEIS

%I #22 Jul 11 2024 14:35:39

%S 36,45,210,300,378,630,780,990,1485,1540,2850,3240,3570,4095,4851,

%T 4950,5460,8778,9180,11781,15400,17955,19110,21528,25200,26565,26796,

%U 31878,33930,37128,37950,39060,40755,43956,52650,61425,61776,70125,79800,82215,97020

%N Triangular numbers which are products of triangular numbers larger than 1.

%H Pontus von Brömssen, <a href="/A068143/b068143.txt">Table of n, a(n) for n = 1..3597</a> (all terms below 10^12).

%e 210 is a term as 210 = 21*10 both triangular numbers.

%e 300 is also a term since 300 = 3*10*10.

%Y Cf. A000217 (triangular numbers), A374374.

%Y Except the first term, row n=3 of A374370 and row n=2 of A374498.

%Y A188630 is a subsequence (only 2 factors allowed).

%K nonn

%O 1,1

%A _Amarnath Murthy_, Feb 23 2002

%E Corrected and extended by _Jon E. Schoenfield_, Jul 23 2006

%E a(38)-a(41) from _Pontus von Brömssen_, Jul 02 2024