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FORMULA
| a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-1)^k*5^(n-k). - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 11 2007
Integral representation: a(n)=(2/pi)*Int(x^n*sqrt(x(20-x))/(x(16+x)),x,0,20). [From Paul Barry (pbarry(AT)wit.ie), Sep 15 2009]
Contribution from Gary W. Adamson, Jul 18 2011: (Start)
a(n) = upper left term in M^n, M = an infinite square production matrix as follows:
4, 4, 0, 0, 0, 0,...
5, 5, 5, 0, 0, 0,...
5, 5, 5, 5, 0, 0,...
5, 5, 5, 5, 5, 0,...
5, 5, 5, 5, 5, 5,...
... (end)
Conjecture: n*a(n)+2*(15-2*n)*a(n-1) +160*(3-2*n)*a(n-2)=0. - R. J. Mathar, Nov 15 2011
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