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A257557 Expansion (x-1)/(x^5+2*x^3+2*x-1). 0

%I #8 Apr 30 2015 21:05:48

%S 1,1,2,6,14,33,79,188,448,1068,2545,6065,14454,34446,82090,195633,

%T 466223,1111080,2647872,6310280,15038353,35838673,85408986,203542550,

%U 485072726,1156001777,2754927327,6565409092,15646364288,37287655956,88862131873

%N Expansion (x-1)/(x^5+2*x^3+2*x-1).

%F a(n) = Sum_{k=0..n} Sum_{i=0..(n-k)/2} C(2*k,i)*C(n-2*i-1,n-2*i-k).

%t CoefficientList[Series[(x - 1)/(x^5 + 2 x^3 + 2 x - 1), {x, 0, 33}], x] (* _Vincenzo Librandi_, Apr 30 2015 *)

%o (Maxima)

%o a(n):=sum(sum(binomial(2*k,i)*binomial(n-2*i-1,n-2*i-k),i,0,(n-k)/2),k,0,n);

%K nonn

%O 0,3

%A _Vladimir Kruchinin_, Apr 29 2015

%E More terms from _Vincenzo Librandi_, Apr 30 2015

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)