A019564 Coordination sequence for C_8 lattice.

1, 128, 2816, 27008, 157184, 658048, 2187520, 6140800, 15158272, 33830016, 69629696, 134110592, 244396544, 425000576, 710003968, 1145628544, 1793234944, 2732779648, 4066763520, 5924704640

Offset

0,2

Links

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

M. Baake and U. Grimm, Coordination sequences for root lattices and related graphs, arXiv:cond-mat/9706122, Zeit. f. Kristallographie, 212 (1997), 253-256.

R. Bacher, P. de la Harpe and B. Venkov, Séries de croissance et séries d'Ehrhart associées aux réseaux de racines, Annales de l'institut Fourier, Tome 49 (1999) no. 3 , p. 727-762.

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.

Formula

G.f.: (1+120*x+1820*x^2+8008*x^3+12870*x^4+8008*x^5+1820*x^6+120*x^7+x^8)/(1-x)^8 = 1+128*x* (x+1)^2*(x^2+6*x+1)^2/(x-1)^8.

a(n) = A008416(2*n). - Seiichi Manyama, Jun 08 2018

Crossrefs

Cf. A008416.

Sequence in context: A297687 A221662 A250282 * A224163 A224414 A128802

Adjacent sequences: A019561 A019562 A019563 * A019565 A019566 A019567

Keyword

nonn,easy

Author

mbaake(AT)sunelc3.tphys.physik.uni-tuebingen.de (Michael Baake)

Status

approved