The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A053990 Numbers of the form x*(x + 1)*y*(y + 1) ("bipronics") where x and y are distinct. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
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
Sequence in context: A085231 A057715 A357863 * A026365 A051435 A187975
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 27 14:41 EDT 2024. Contains 372861 sequences. (Running on oeis4.)