%I #6 Jun 06 2013 11:49:31

%S 210,630,780,990,1326,1540,1596,1770,1830,2145,2346,2415,2850,2926,

%T 3003,3486,3570,3828,4095,4186,4278,4560,4950,5460,5565,6105,6216,

%U 6555,6670,6786,7140,7260,7626,8385,8646,8778,9180,9730,9870,10296,10440,10878

%N Triangular numbers with more than three distinct prime factors.

%H Harvey P. Dale, <a href="/A121479/b121479.txt">Table of n, a(n) for n = 1..1000</a>

%e 20*21/2 = 2*3*5*7 = 210 is the smalles triangular number with more than three distinct prime factors, hence a(1) = 210.

%t Select[Accumulate[Range[200]],PrimeNu[#]>3&] (* _Harvey P. Dale_, Jun 06 2013 *)

%o (PARI) for(n=1,100,k=binomial(n+1,2);if(omega(k)>3,print1(k,",")))

%Y Cf. A000217, A068443, A119663, A121478.

%K easy,nonn

%O 1,1

%A _Klaus Brockhaus_, Aug 01 2006