A035609 Coordination sequence for lattice D*_20 (with edges defined by l_1 norm = 1).

1, 40, 800, 10680, 107200, 864008, 5831520, 33940120, 174074240, 800061160, 3340552608, 12819218040, 45663942720, 152270990280, 478683156960, 1426865410392, 4052167914240, 11006991835560, 28691971995680, 71976895917880

Offset

0,2

Links

Table of n, a(n) for n=0..19.

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

a(m)=add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n)+2^n*binomial((n+2*m)/2-1, n-1); with n=20.

Crossrefs

Sequence in context: A006240 A126928 A035715 * A161653 A162176 A162402

Adjacent sequences: A035606 A035607 A035608 * A035610 A035611 A035612

Keyword

nonn

Author

N. J. A. Sloane, J. Serra-Sagrista (jserra(AT)ccd.uab.es)

Status

approved