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

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. 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