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A158197

Expansion of (1-x^2*c(x)^4)/(1-4*x*c(x)^2), c(x) the g.f. of A000108.

1, 4, 23, 140, 866, 5388, 33603, 209796, 1310510, 8188328, 51169094, 319779544, 1998527188, 12490460620, 78064190235, 487896926580, 3049340393430, 19058321475960, 119114304522450, 744463650984360, 4652895041524380

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OFFSET

0,2

COMMENTS

Apply the inverse of the Riordan array (1/(1-x^2),x/(1+x)^2) to 4^n. Hankel transform is A070997.

LINKS

Table of n, a(n) for n=0..20.

FORMULA

Conjecture: +4*(n+1)*a(n) +(-81*n+23)*a(n-1) +10*(51*n-70)*a(n-2) +500*(-2*n+5)*a(n-3)=0. - R. J. Mathar, Feb 05 2015

Conjecture: +4*(n+1)^2*a(n) +(-41*n^2-58*n+23)*a(n-1) +50*(n+2)*(2*n-3)*a(n-2)=0. - R. J. Mathar, Feb 05 2015

CROSSREFS

Cf. A000108, A070997, A090317, A158196.

Sequence in context: A237362 A067110 A290052 * A356282 A038736 A091642

Adjacent sequences: A158194 A158195 A158196 * A158198 A158199 A158200

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Mar 13 2009

STATUS

approved

URL: https://oeis.org/A158197

⇱ A158197 - OEIS