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.
1, 5, 17, 63, 242, 922, 3502, 13311, 50608, 192398, 731429, 2780649, 10571120, 40187929, 152781292, 580824261, 2208102985, 8394481949, 31913061839, 121322974122, 461230079570, 1753445197282, 6666022438759, 25342026784200
Offset: 0
Keywords
Crossrefs
Cf. A099527.
Programs
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PARI
a(n)=sum(k=0,n,polcoeff((2+3*z+z^2+z*O(z^k))^(n-k\2),k,z))
Formula
G.f.: (1+x-x^2)/(1-4*x+2*x^2-5*x^3+x^4).
Extensions
Corrected by T. D. Noe, Oct 25 2006