A134858 Numbers that can be written as (a^2 - 1)(b^2 - 1) in five or more distinct ways.

588107520, 67270694400, 546939993600, 2128050512640, 37400697734400, 5566067918611200

Offset

1,1

Comments

Subsequence of A134856 and A134857.

Depending on the interpretation of A057535, this is either the same or a supersequence of A057535. [R. J. Mathar, Oct 16 2009]

The next term (if it exists) is greater than 2^70.

Links

Table of n, a(n) for n=1..6.

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

Example

588107520 = (13^2 - 1)(1871^2 - 1) = (17^2 - 1)(1429^2 - 1) = (55^2 - 1)(441^2 - 1) = (79^2 - 1)(307^2 - 1) = (129^2 - 1)(188^2 - 1).

Crossrefs

Cf. A057535, A134857, A134856, A063067, A063066, A063068.

Sequence in context: A234391 A297448 A057535 * A344928 A344929 A145277

Adjacent sequences: A134855 A134856 A134857 * A134859 A134860 A134861

Keyword

hard,more,nonn

Author

Herman Beeksma, Nov 13 2007

Status

approved