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Hypotenuses of Pythagorean triples in A195499 and A195503.
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%I #17 Apr 08 2012 20:18:30

%S 5,17,65,241,901,3361,12545,46817,174725,652081,2433601,9082321,

%T 33895685,126500417,472105985,1761923521,6575588101,24540428881,

%U 91586127425,341804080817,1275630195845,4760716702561,17767236614401,66308229755041

%N Hypotenuses of Pythagorean triples in A195499 and A195503.

%C See A195500 for discussion and list of related sequences; see A195499 for Mathematica program.

%C Essentially the same as A120893. - R. J. Mathar, Sep 21 2011

%F Conjecture: a(n) = 3*a(n-1)+3*a(n-2)-a(n-3). G.f.: x*(5+2*x-x^2)/((1+x)*(1-4*x+x^2)). [Colin Barker, Apr 08 2012]

%Y Cf. A195500, A195499, A195503.

%K nonn

%O 1,1

%A _Clark Kimberling_, Sep 20 2011