A053990 Numbers of the form x*(x + 1)*y*(y + 1) ("bipronics") where x and y are distinct.

0, 12, 24, 40, 60, 72, 84, 112, 120, 144, 180, 220, 240, 252, 264, 312, 336, 360, 364, 420, 432, 480, 504, 540, 544, 600, 612, 660, 672, 684, 760, 792, 840, 864, 924, 936, 1012, 1080, 1092, 1104, 1120, 1200, 1260, 1300, 1320, 1404, 1440, 1512, 1584, 1624

Offset: 1

Author

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

Keywords

• nonn
• easy

Examples

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

Crossrefs

Cf. A054731, A054734, A072389.

Programs

Mathematica

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

Extensions

More terms from James Sellers, Apr 22 2000