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Numbers expressible as (a^2-1)(b^2-1) in at least 2 distinct ways (b>=a>1).
7

%I #6 Aug 20 2012 20:35:35

%S 360,504,2304,2520,2880,3465,5040,5400,7920,9360,12285,12600,12672,

%T 13440,14400,17325,20160,23040,27720,28224,29400,30600,32760,35640,

%U 38080,40320,42840,47880,48384,49920,51480,57960,60480,63360,72072

%N Numbers expressible as (a^2-1)(b^2-1) in at least 2 distinct ways (b>=a>1).

%H Donovan Johnson, <a href="/A063067/b063067.txt">Table of n, a(n) for n = 1..1000</a>

%H K. S. Brown, <a href="http://www.mathpages.com/home/kmath275.htm">Numbers Expressible as (a^2-1)(b^2-1)</a>

%e 360 is on the list since 360 = (2^2-1)(11^2-1) = (4^2-1)(5^2-1).

%Y Cf. A057535, A063066, A063068.

%K nonn

%O 1,1

%A _Henry Bottomley_, Jul 08 2001

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