A063066 Numbers expressible as (a^2-1)(b^2-1).

9, 24, 45, 64, 72, 105, 120, 144, 189, 192, 225, 240, 280, 297, 360, 384, 429, 504, 525, 576, 585, 640, 672, 720, 765, 792, 840, 864, 945, 960, 969, 1080, 1144, 1152, 1197, 1200, 1225, 1320, 1344, 1449, 1485, 1512, 1560, 1584, 1680, 1725, 1792, 1800, 1872

Offset

1,1

Links

Table of n, a(n) for n=1..49.

K. S. Brown, Numbers Expressible as (a^2-1)(b^2-1)

Example

45 is on the list because 45=(2^2-1)(4^2-1)

Mathematica

With[{nn=50}, Take[(#[[1]]^2-1)(#[[2]]^2-1)&/@Tuples[Range[2, nn], 2]//Union, nn]] (* Harvey P. Dale, May 29 2017 *)

Crossrefs

Cf. A057535, A063067, A063068.

Sequence in context: A293846 A212462 A161449 * A262044 A362420 A097658

Adjacent sequences: A063063 A063064 A063065 * A063067 A063068 A063069

Keyword

nonn

Author

Henry Bottomley, Jul 08 2001

Status

approved