A200540 Product of Pell and Motzkin numbers: a(n) = A000129(n+1)*A001006(n).

1, 2, 10, 48, 261, 1470, 8619, 51816, 318155, 1985630, 12561308, 80360280, 519013571, 3379514970, 22161470850, 146227235904, 970126550763, 6467496499590, 43304243215638, 291087137589552, 1963598081845335, 13288619577124122, 90195242361688863, 613843707553183800

Offset

0,2

Comments

The g.f. for the Pell numbers is 1/(1-2*x-x^2) and the g.f. M(x) for the Motzkin numbers satisfy: M(x) = 1 + x*M(x) + x^2*M(x)^2.

Links

Table of n, a(n) for n=0..23.

Example

G.f.: A(x) = 1 + 2*x + 10*x^2 + 48*x^3 + 261*x^4 + 1470*x^5 + 8619*x^6 +...
where A(x) = 1*1 + 2*1*x + 5*2*x^2 + 12*4*x^3 + 29*9*x^4 + 70*21*x^5 + 169*51*x^6 + 408*127*x^7 + 985*323*x^8 +...+ A000129(n+1)*A001006(n)*x^n +...

Prog

(PARI) {A001006(n)=polcoeff((1-x-sqrt((1-x)^2-4*x^2+x^3*O(x^n)))/(2*x^2), n)}
{A000129(n)=polcoeff( x/(1-2*x-x^2+x*O(x^n)), n)}
{a(n)=A000129(n+1)*A001006(n)}

Crossrefs

Cf. A098616, A200538, A200539, A098614.

Sequence in context: A114693 A086853 A036918 * A166922 A302557 A129118

Adjacent sequences: A200537 A200538 A200539 * A200541 A200542 A200543

Keyword

nonn

Author

Paul D. Hanna, Nov 18 2011

Status

approved