A134857 - OEIS

A134857

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

241920, 1048320, 10200960, 25724160, 37255680, 93139200, 123963840, 245044800, 588107520, 819786240, 1407893760, 1871251200, 3758169600, 5886558720, 8553283200, 10783342080, 13470367680, 19769460480, 30791819520, 40446806400

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OFFSET

1,1

COMMENTS

Subsequence of A134856. Contains A134858 as a subsequence.

LINKS

Table of n, a(n) for n=1..20.

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

EXAMPLE

241920 = (4^2-1)(127^2-1) = (7^2-1)(71^2-1) = (9^2-1)(55^2-1) = (17^2-1)(29^2-1).

CROSSREFS

Cf. A134856, A134858.

Cf. A057535, A063066, A063067, A063068.

Sequence in context: A249194 A281887 A127881 * A251007 A078871 A249209

Adjacent sequences: A134854 A134855 A134856 * A134858 A134859 A134860

KEYWORD

easy,nonn

AUTHOR

Herman Beeksma, Nov 13 2007

STATUS

approved