A195531 Hypotenuses of Pythagorean triples in A195499 and A195503.

5, 17, 65, 241, 901, 3361, 12545, 46817, 174725, 652081, 2433601, 9082321, 33895685, 126500417, 472105985, 1761923521, 6575588101, 24540428881, 91586127425, 341804080817, 1275630195845, 4760716702561, 17767236614401, 66308229755041

Offset: 1

Author

Clark Kimberling, Sep 20 2011

Keywords

• nonn
• changed

Comments

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

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

Crossrefs

Cf. A195500, A195499, A195503.

Formula

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