

A304202


a(n) = (2*n3)*4^(n1)  2*binomial(2*n, n1).


0



18, 208, 1372, 7632, 39050, 190112, 895524, 4120528, 18629652, 83088096, 366560568, 1602837280, 6956911962, 30007067456, 128736063316, 549740689872, 2338025684540, 9907917740128, 41853370268424, 176294674155104, 740683257681988, 3104678088923328, 12986226585328232
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OFFSET

3,1


LINKS

Table of n, a(n) for n=3..25.
Sihuang Hu and Gabriele Nebe, Strongly perfect lattices sandwiched between BarnesWall lattices, arXiv:1805.01196 [math.NT], 2018. See p. 21.


FORMULA

E.g.f.: (3 + 12*x + 8*x^2  3*exp(4*x) + 8*exp(4*x)*x  8*exp(2*x)*I_1(2*x) )/4, where I_1(.) is the modified Bessel function of the first kind.  Bruno Berselli, May 08 2018
(n+1)*(2*n^27*n+7)*a(n)  2*n*(4*n5)*(2*n3)*a(n1) + 8*(2*n3)*(2*n^23*n+2)*a(n2) = 0.  R. J. Mathar, May 08 2018


MATHEMATICA

Table[(2 n  3) 4^(n  1)  2 Binomial[2 n, n  1], {n, 3, 40}]


PROG

(MAGMA) [(2*n3)*4^(n1)2*Binomial(2*n, n1): n in [3..20]];


CROSSREFS

Cf. A144704, A162551.
Sequence in context: A109126 A022742 A055528 * A298988 A025959 A229270
Adjacent sequences: A304199 A304200 A304201 * A304203 A304204 A304205


KEYWORD

nonn,easy


AUTHOR

Vincenzo Librandi, May 08 2018


STATUS

approved



