A166076 Expansion of (7+5x-sqrt(1-10x-7x^2))/(2(3+5x+2x^2)).

1, 0, 2, 10, 70, 530, 4278, 36050, 313558, 2793970, 25374262, 234016530, 2185799958, 20634634930, 196569384566, 1887215137490, 18242042039894, 177383206638450, 1733967807665334, 17029818475966610, 167961197068279190

Offset

0,3

Comments

First column of inverse of Riordan array ((1+x)/(1+x+2x^2),x(1-2x)/(1+x+2x^2)).

Hankel transform is A166077.

Links

G. C. Greubel, Table of n, a(n) for n = 0..500

Formula

Conjecture: 3*(n)*a(n) +5*(-5*n+9)*a(n-1) +69*(-n+2)*a(n-2) +5*(-11*n+27)*a(n-3) +14*(-n+3)*a(n-4)=0. - R. J. Mathar, Feb 10 2015

Mathematica

CoefficientList[Series[(7+5x-Sqrt[1-10x-7x^2])/(2(3+5x+2x^2)), {x, 0, 30}], x] (* Harvey P. Dale, Nov 26 2011 *)

Crossrefs

Sequence in context: A259114 A051575 A121201 * A354307 A217938 A333902

Adjacent sequences: A166073 A166074 A166075 * A166077 A166078 A166079

Keyword

easy,nonn

Author

Paul Barry, Oct 06 2009

Status

approved