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A109222
Row sums of a triangle related to the Fibonacci polynomials.
4
1, 2, 3, 6, 11, 21, 40, 76, 145, 276, 526, 1002, 1909, 3637, 6929, 13201, 25150, 47915, 91286, 173915, 331337, 631252, 1202640, 2291229, 4365172, 8316378, 15844082, 30185609, 57508601, 109563441, 208736561, 397677834, 757642355, 1443434582
OFFSET
0,2
COMMENTS
Row sums of A109221.
The Kn4 sums, see A180662, of triangle A065941 equal the terms of this sequence a(n) while the Kn4 sums of triangle A194005 equal a(n+1)-1. - Johannes W. Meijer, Aug 14 2011
FORMULA
G.f.: (1 + x - x^2 - x^3)/(1 - x - 2x^2 + x^4);
a(n) = a(n-1) + 2a(n-2) - a(n-4);
a(n) = Sum_{k=0..n} binomial(floor((2n-k)/2)+n-k, 2n-2k).
MAPLE
A109222 := proc(n): add(binomial(floor((2*n-k)/2)+n-k, 2*n-2*k), k=0..n) end: seq(A109222(n), n=0..33); # Johannes W. Meijer, Aug 14 2011
CROSSREFS
Sequence in context: A132832 A316796 A079116 * A191789 A371790 A306575
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jun 22 2005
STATUS
approved