A238755 Second convolution of A065096.
0, 0, 1, 12, 98, 684, 4403, 27048, 161412, 945288, 5466549, 31340628, 178604998, 1013573652, 5735117479, 32385232272, 182622362504, 1028897389008, 5793703249449, 32615362319580, 183593293074730, 1033535639454780, 5819389057957211, 32775522041862072, 184658694508103180
Offset: 0
Links
- Fung Lam, Table of n, a(n) for n = 0..1300
Programs
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Mathematica
CoefficientList[Series[(1-3*x-Sqrt[1-6*x+x^2])^4/(16*x^3)^2, {x, 0, 20}], x] (* Vaclav Kotesovec, Mar 05 2014 *) -
PARI
x='x+O('x^50); concat([0,0], Vec((1-3*x-sqrt(1-6*x+x^2))^4/(16*x^3)^2)) \\ G. C. Greubel, Apr 05 2017
Formula
G.f. = (G.f. of A065096)^2.
Recurrence: (n+6)*a(n) = 225*(6-n)*a(n-8) + 1020*(2*n-9)*a(n-7) + 5164*(3-n)*a(n-6) + 76*(78*n-117)*a(n-5) - 3590*n*a(n-4) + 36*(34*n+51)*a(n-3) - 236*(n+3)*a(n-2) + 12*(2*n+9)*a(n-1), n>=8.
Recurrence (of order 2): (n-2)*(n+6)*a(n) = 3*(n+1)*(2*n+3)*a(n-1) - n*(n+1)*a(n-2). - Vaclav Kotesovec, Mar 05 2014
a(n) ~ (3*sqrt(2)-4)^(7/2) * (3+2*sqrt(2))^(n+6) / (8*sqrt(Pi)*n^(3/2)). - Vaclav Kotesovec, Mar 05 2014