A035715 Coordination sequence for 20-dimensional cubic lattice.

1, 40, 800, 10680, 107200, 864008, 5831520, 33940120, 174074240, 800061160, 3339504032, 12798246520, 45443741760, 150656183240, 469398016480, 1382296736088, 3866465104640, 10317238542760, 26364054632480, 64734486343480

Offset

0,2

Links

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

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.

Index entries for linear recurrences with constant coefficients, signature (20, -190, 1140, -4845, 15504, -38760, 77520, -125970, 167960, -184756, 167960, -125970, 77520, -38760, 15504, -4845, 1140, -190, 20, -1).

Formula

G.f.: ((1+x)/(1-x))^20.

n*a(n) = 40*a(n-1) + (n-2)*a(n-2) for n > 1. - Seiichi Manyama, Aug 20 2018

Mathematica

CoefficientList[Series[((1+x)/(1-x))^20, {x, 0, 30}], x] (* Harvey P. Dale, Mar 26 2016 *)

Crossrefs

Sequence in context: A010956 A006240 A126928 * A035609 A161653 A162176

Adjacent sequences: A035712 A035713 A035714 * A035716 A035717 A035718

Keyword

nonn,easy

Author

Joan Serra-Sagrista (jserra(AT)ccd.uab.es)

Extensions

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

Status

approved