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

1,2

Links

Table of n, a(n) for n=1..50.

Example

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

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 *)

Crossrefs

Cf. A054731, A054734, A072389.

Sequence in context: A085231 A057715 A357863 * A026365 A051435 A187975

Adjacent sequences: A053987 A053988 A053989 * A053991 A053992 A053993

Keyword

nonn,easy

Author

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

Extensions

More terms from James A. Sellers, Apr 22 2000

Status

approved