The On-Line Encyclopedia of Integer Sequences (OEIS)

A035894 revision #13

A035894

Coordination sequence for diamond structure D^+_36. (Edges defined by l_1 norm = 1.)

1, 0, 2592, 0, 1121472, 0, 194986080, 0, 18300435840, 0, 1080041397408, 0, 44042615547456, 0, 1323529602867936, 0, 30721376739859200, 0, 570951082378155808, 1236950581248, 8740628929823039424

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..20.

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=36.

CROSSREFS

Sequence in context: A236351 A250241 A252152 * A179702 A258728 A326747

Adjacent sequences: A035891 A035892 A035893 * A035895 A035896 A035897

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

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

STATUS

editing