A053990 - OEIS

%I #6 Jun 01 2012 14:22:18

%S 0,12,24,40,60,72,84,112,120,144,180,220,240,252,264,312,336,360,364,

%T 420,432,480,504,540,544,600,612,660,672,684,760,792,840,864,924,936,

%U 1012,1080,1092,1104,1120,1200,1260,1300,1320,1404,1440,1512,1584,1624

%N Numbers of the form x*(x + 1)*y*(y + 1) ("bipronics") where x and y are distinct.

%e Taking x=1, y=2 gives 2 * 6 =12

%t bipr[{a_,b_}]:=a(a+1)b(b+1); Take[Union[bipr/@Subsets[Range[0,40], {2}]],50] (* _Harvey P. Dale_, Jun 01 2012 *)

%Y Cf. A054731, A054734, A072389.

%K nonn,easy

%O 1,2

%A Stuart M. Ellerstein (ellerstein(AT)aol.com), Apr 04 2000

%E More terms from _James A. Sellers_, Apr 22 2000