OFFSET
0,2
REFERENCES
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (see p. 313).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..555
FORMULA
a(n) = (2*binomial(2*n,n) - 1)*(binomial(2*n,n)^2 - binomial(2*n,n) + 1).
G.f.: 3/sqrt(1 - 4*x) - 1/(1 - x) + (8*EllipticK((1/2)*(1 - sqrt(1 - 64*x)))^2)/Pi^2 - (6*EllipticK(16*x))/Pi. - G. C. Greubel, Sep 06 2017
MAPLE
a:=n->(2*binomial(2*n, n)-1)*(binomial(2*n, n)^2-binomial(2*n, n)+1); seq(a(n), n=0..16);
MATHEMATICA
Table[(2*Binomial[2*n, n] - 1)*(Binomial[2*n, n]^2 - Binomial[2*n, n] + 1), {n, 0, 50}] (* G. C. Greubel, Sep 06 2017 *)
PROG
(PARI) for(n=0, 25, print1((2*binomial(2*n, n) - 1)*(binomial(2*n, n)^2 - binomial(2*n, n) + 1), ", ")) \\ G. C. Greubel, Sep 06 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Aug 03 2005
STATUS
approved