A158196 Expansion of (1-x^2*c(x)^4)/(1-3*x*c(x)^2), c(x) the g.f. of A000108.

1, 3, 14, 71, 370, 1950, 10332, 54895, 292106, 1555706, 8289732, 44186710, 235575028, 1256093084, 6698073528, 35719158591, 190488112122, 1015885525794, 5417869631028, 28894620083346, 154102115782812

Offset

0,2

Comments

Apply the inverse of the Riordan array (1/(1-x^2),x/(1+x)^2) to 3^n. Hankel transform is A001653.

Links

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

Formula

Conjecture: +3*(n+1)*a(n) +2*(-26*n+7)*a(n-1) +16*(18*n-25)*a(n-2) +256*(-2*n+5)*a(n-3)=0. - R. J. Mathar, Feb 05 2015

Conjecture: 3*(2*n+3)*(n+1)*a(n) +2*(-28*n^2-52*n+21)*a(n-1) +32*(2*n+5)*(2*n-3)*a(n-2)=0. - R. J. Mathar, Feb 05 2015

Crossrefs

Cf. A090317.

Sequence in context: A186765 A109792 A137177 * A191649 A009637 A098648

Adjacent sequences: A158193 A158194 A158195 * A158197 A158198 A158199

Keyword

easy,nonn

Author

Paul Barry, Mar 13 2009

Status

approved