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A216541 Product of Lucas and Catalan numbers: a(n) = A000032(n+1)*A000108(n). 0
1, 3, 8, 35, 154, 756, 3828, 20163, 108680, 598026, 3342404, 18929092, 108374252, 626264700, 3647936160, 21396522915, 126262239570, 749087596620, 4465444206300, 26733390275130, 160663411399920, 968937572793060, 5862111195487560, 35569106862459300 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

FORMULA

G.f.: (1 - sqrt( (1-2*x + sqrt(1-4*x-16*x^2))/2 )) / x.

G.f. satisfies: A(x) = (2+5*x) - (1+4*x)*A(x) + x*(5+2*x)*A(x)^2 - 4*x^2*A(x)^3 + x^3*A(x)^4.

n*(n+1)*a(n) -2*n*(2n-1)*a(n-1) -4*(2*n-1)*(2*n-3)*a(n-2)=0. - R. J. Mathar, Sep 11 2012

EXAMPLE

G.f.: A(x) = 1 + 3*x + 8*x^2 + 35*x^3 + 154*x^4 + 756*x^5 + 3828*x^6 +...

such that the coefficients equal the term-wise products:

A = [1*1, 3*1, 4*2, 7*5, 11*14, 18*42, 29*132, 47*429, 76*1430, ...].

PROG

(PARI) {a(n)=(2*fibonacci(n)+fibonacci(n+1))*binomial(2*n, n)/(n+1)}

(PARI) {a(n)=polcoeff( (1 - sqrt( (1-2*x + sqrt(1-4*x-16*x^2 +x^2*O(x^n)))/2 )) / x, n)}

for(n=0, 25, print1(a(n), ", "))

CROSSREFS

Cf. A098614, A215931, A098616, A000032, A000108.

Sequence in context: A148918 A304726 A226679 * A347896 A194090 A294385

Adjacent sequences:  A216538 A216539 A216540 * A216542 A216543 A216544

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Sep 08 2012

STATUS

approved

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Last modified September 23 03:36 EDT 2021. Contains 347609 sequences. (Running on oeis4.)