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A035857 Coordination sequence for A_31 lattice. 0
1, 992, 246512, 27390112, 1728939192, 70807488864, 2048715010256, 44450256810016, 755891034102316, 10424936982850656, 119820002520271088, 1173396885194646560, 9972151083876157960, 74688593871319112160 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

R. Bacher, P. de la Harpe and B. Venkov, Series de croissance et series d'Ehrhart associees aux reseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.

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..13.

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

Index entries for linear recurrences with constant coefficients, signature (31, -465, 4495, -31465, 169911, -736281, 2629575, -7888725, 20160075, -44352165, 84672315, -141120525, 206253075, -265182525, 300540195, -300540195, 265182525, -206253075, 141120525, -84672315, 44352165, -20160075, 7888725, -2629575, 736281, -169911, 31465, -4495, 465, -31, 1).

FORMULA

Sum_{d=1..31} C(32, d)*C(m/2-1, d-1)*C(31-d+m/2, m/2), where norm m is always even.

CROSSREFS

Sequence in context: A183973 A181601 A181707 * A028513 A267119 A210315

Adjacent sequences:  A035854 A035855 A035856 * A035858 A035859 A035860

KEYWORD

nonn,easy

AUTHOR

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

STATUS

approved

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Last modified January 27 16:41 EST 2022. Contains 350611 sequences. (Running on oeis4.)