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LinearRecurrence[{20, -170, 780, -1965, 2064, 1800, -6480, 1710, 8600, -3772, -8600, 1710, 6480, 1800, -2064, -1965, -780, -170, -20, -1}, {1, 20, 230, 1980, 14135, 88264, 497860, 2591160, 12630475, 58295380, 256887774, 1087825180, 4449607565, 17654254880, 68177369040, 257006941664, 948023601910, 3428968838680, 12182953719860, 42585118702280}, 20] (* Harvey P. Dale, Nov 20 2022 *)

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For a(n) in terms of U(n+1) and U(n) with U(n) := A000129(n+1) see the row polynomials of triangles A058402 and A058403 and the comment there.

G. C. Greubel, <a href="/A073386/b073386.txt">Table of n, a(n) for n = 0..1000</a>

<a href="/index/Rec#order_20">Index entries for linear recurrences with constant coefficients</a>, signature (20,-170,780,-1965,2064,1800,-6480,1710,8600,-3772, -8600,1710,6480,1800,-2064,-1965,-780,-170,-20,-1).

a(n) = sum(Sum_{k=0..n} b(k)*c(n-k), k=0..n) with b(k) := A000129(k+1) and c(k) := A073385(k).

a(n) = sum(Sum_{k=0..floor(n/2)} 2^(n-2*k)*binomial(n-k+9, 9)*binomial(n-k, k)*(1/4)^k, k=0..floor(n/2)).

CoefficientList[Series[1/(1-2*x-x^2)^10, {x, 0, 40}], x] (* G. C. Greubel, Oct 03 2022 *)

(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1/(1-2*x-x^2)^10 )); // G. C. Greubel, Oct 03 2022

(SageMath)

def A073386_list(prec):

P.<x> = PowerSeriesRing(ZZ, prec)

return P( 1/(1-2*x-x^2)^10 ).list()

A073386_list(40) # G. C. Greubel, Oct 03 2022

Cf. A000129, A058402, A058403, A073385.

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a(n) = sum(b(k)*c(n-k), k=0..n) with b(k) := A000129(k+1) and c(k) := A073385(k).

a(n) = sum((2^n)*binomial(n-k+9, 9)*binomial(n-k, k)*(1/4)^k, k=0..floor(n/2)).

a(n) = F'''''''''(n+10, 2)/9!, that is, 1/9! times the 9th derivative of the (n+10)th Fibonacci polynomial evaluated at x=2. - T. D. Noe, Jan 19 2006

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