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A134857
Numbers that can be written as (a^2-1)(b^2-1) in four or more distinct ways.
4
241920, 1048320, 10200960, 25724160, 37255680, 93139200, 123963840, 245044800, 588107520, 819786240, 1407893760, 1871251200, 3758169600, 5886558720, 8553283200, 10783342080, 13470367680, 19769460480, 30791819520, 40446806400
OFFSET
1,1
COMMENTS
Subsequence of A134856. Contains A134858 as a subsequence.
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
KEYWORD
easy,nonn
AUTHOR
Herman Beeksma, Nov 13 2007
STATUS
approved