login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A035887 Coordination sequence for diamond structure D^+_22. (Edges defined by l_1 norm = 1.) 0
1, 0, 968, 0, 156816, 0, 10286936, 0, 368804128, 0, 8453107432, 2097152, 136631618992, 530579456, 1668180181624, 26528972800, 16189344891456, 620777963520, 129752349166088, 9001280471040, 883945662928592 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

J. Serra-Sagrista, Enumeration of lattice points in l_1 norm, Information Processing Letters, 76, no. 1-2 (2000), 39-44.

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).

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=22.

CROSSREFS

Sequence in context: A246477 A064258 A142378 * A255656 A035759 A107555

Adjacent sequences:  A035884 A035885 A035886 * A035888 A035889 A035890

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 25 17:22 EDT 2021. Contains 348255 sequences. (Running on oeis4.)