A134856 Numbers that can be written as (a^2-1)(b^2-1) in three or more distinct ways.

2880, 27720, 40320, 49920, 63360, 98280, 241920, 282744, 491400, 547200, 604800, 950400, 970200, 1048320, 1370880, 1614600, 1774080, 2489760, 2608320, 2882880, 2923200, 3931200, 4817400, 6126120, 7338240, 7673400, 8426880, 10200960

Offset

1,1

Comments

Contains A134857 and A134858 as subsequences.

Links

Table of n, a(n) for n=1..28.

MathPages, Numbers Expressible As (a^2-1)(b^2-1).

Example

2880 = (2^2-1)(31^2-1) = (3^2-1)(19^2-1) = (5^2-1)(11^2-1).

Crossrefs

Cf. A134857, A134858, A057535, A063066, A063067, A063068.

Sequence in context: A175750 A179703 A260369 * A066407 A184602 A144547

Adjacent sequences: A134853 A134854 A134855 * A134857 A134858 A134859

Keyword

easy,nonn

Author

Herman Beeksma, Nov 13 2007

Status

approved