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A200538 Product of Jacobsthal and Motzkin numbers: a(n) = A001045(n+1)*A001006(n). 2
1, 1, 6, 20, 99, 441, 2193, 10795, 55233, 284735, 1494404, 7914270, 42360541, 228460935, 1241224182, 6784445340, 37288826697, 205937705799, 1142317727466, 6361104740100, 35548154733969, 199295884785459, 1120615326442269, 6318077793648075, 35710056983891367, 202297486497822121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The g.f. for the Jacobsthal numbers is 1/(1-x-2*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..25.

EXAMPLE

G.f.: A(x) = 1 + x + 6*x^2 + 20*x^3 + 99*x^4 + 441*x^5 + 2193*x^6 +...

where A(x) = 1*1 + 1*1*x + 3*2*x^2 + 5*4*x^3 + 11*9*x^4 + 21*21*x^5 + 43*51*x^6 + 85*127*x^7 + 171*323*x^8 +...+ A001045(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)}

{A001045(n)=polcoeff( x/(1-x-2*x^2+x*O(x^n)), n)}

{a(n)=A001045(n+1)*A001006(n)}

CROSSREFS

Cf. A200375, A200539, A200540, A001045, A001006.

Sequence in context: A226638 A151485 A191424 * A238118 A211953 A207819

Adjacent sequences:  A200535 A200536 A200537 * A200539 A200540 A200541

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Nov 18 2011

STATUS

approved

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Last modified April 16 02:33 EDT 2014. Contains 240534 sequences.