A099528 - OEIS

A099528

Row sums of triangle A099527, so that a(n) = Sum_{k=0..n} coefficient of z^k in (2 + 3*z + z^2)^(n-[k/2]), where [k/2] is the integer floor of k/2.

%I #5 Mar 30 2012 18:36:43

%S 1,5,17,63,242,922,3502,13311,50608,192398,731429,2780649,10571120,

%T 40187929,152781292,580824261,2208102985,8394481949,31913061839,

%U 121322974122,461230079570,1753445197282,6666022438759,25342026784200

%N Row sums of triangle A099527, so that a(n) = Sum_{k=0..n} coefficient of z^k in (2 + 3*z + z^2)^(n-[k/2]), where [k/2] is the integer floor of k/2.

%F G.f.: (1+x-x^2)/(1-4*x+2*x^2-5*x^3+x^4).

%o (PARI) a(n)=sum(k=0,n,polcoeff((2+3*z+z^2+z*O(z^k))^(n-k\2),k,z))

%Y Cf. A099527.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Oct 20 2004

%E Corrected by _T. D. Noe_, Oct 25 2006