A035921 Coordination sequence for diamond structure D^+_90. (Edges defined by l_1 norm = 1.)

1, 0, 16200, 0, 43750800, 0, 47297528280, 0, 27425793987360, 0, 9912269336940648, 0, 2448015194902257840, 0, 439668298578779894520, 0, 60071753985937273120320, 0, 6460749140008058788098440, 0, 561838152794479347081022416, 0, 40369733975261540188277953560, 0, 2439893679823103970428776675680, 0

Offset

0,3

Links

Georg Fischer, Table of n, a(n) for n = 0..200

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.

Maple

f := proc(m) local k, t1; t1 := 2^(n-1)*binomial((n+2*m)/2-1, n-1); if m mod 2 = 0 then t1 := t1+add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n); fi; t1; end; where n=90.

Crossrefs

Sequence in context: A236872 A031843 A031624 * A278607 A235845 A254163

Adjacent sequences: A035918 A035919 A035920 * A035922 A035923 A035924

Keyword

nonn

Author

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

Extensions

Recomputed by N. J. A. Sloane, Nov 27 1998

Zeroes inserted by Georg Fischer, Jul 26 2020

Status

approved