A053990 - OEIS

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

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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 A375662