1,1

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

Table of n, a(n) for n=1..24.

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]

Cf. A195500, A195499, A195503.

Sequence in context: A273793 A196926 A120893 * A273535 A149672 A149673

Adjacent sequences: A195528 A195529 A195530 * A195532 A195533 A195534

nonn

Clark Kimberling, Sep 20 2011

approved