A035767 Coordination sequence for C_30 lattice.

1, 1800, 541200, 65520920, 4296107040, 177923724072, 5119703270960, 109262828065080, 1814077233023040, 24302419569598280, 270376971905976912, 2557028677258648920, 20954617154922097760, 151203821860764511080, 973794385663429365360, 5662556669152122153336

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

R. Bacher, P. de la Harpe and B. Venkov, Séries de croissance et séries d'Ehrhart associées aux réseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

Joan Serra-Sagrista, Enumeration of lattice points in l_1 norm, Inf. Proc. Lett. 76 (1-2) (2000) 39-44.

Formula

a(n) = [x^(2n)] ((1+x)/(1-x))^30.

Prog

(PARI) a(n) = polcoeff(Pol(((1+x)/(1-x))^30+O(x^(2*n+1))), 2*n); \\ Michel Marcus, Jul 07 2018

Crossrefs

Sequence in context: A179695 A375013 A025139 * A107563 A020402 A180685

Adjacent sequences: A035764 A035765 A035766 * A035768 A035769 A035770

Keyword

nonn,easy

Author

Recomputed by N. J. A. Sloane, Nov 25 1998

Status

approved