%I #9 Feb 28 2013 17:25:39
%S 6,36,91,120,210,253,300,378,528,630,1176,2016,2346,3003,3240,3828,
%T 4560,4656,4950,5460,6105,6903,7140,7260,8778,10296,11628,13530,14028,
%U 14196,15400,17766,19110,23220,23436,24310,25200,26796,32640,34980,41616,43365,44253,52326,55278
%N Triangular numbers which are leg of a Pythagorean triple with hypotenuse in A213188.
%e Triangular 91 and triangular 325 form a Pythagorean triple {325, 91, 312}.
%o (PARI) {for(i=1,10^3,k=i+1;v=1;a=i*(i+1)/2;while(k<i*i&&v,b=k*(k+1)/2;if(issquare(b*b-a*a),v=0;print1(a,", "));k+=1))}
%Y Cf. A213188.
%K nonn
%O 1,1
%A _Antonio Roldán_, Feb 28 2013