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Search: id:A035603
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| A035603 |
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Number of points of L1 norm 9 in cubic lattice Z^n. |
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+0
2
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| 0, 2, 36, 326, 1992, 9290, 35436, 115598, 332688, 864146, 2060980, 4573910, 9545560, 18892250, 35704060, 64797470, 113461024, 192441122, 317222212, 509663334, 800061160, 1229718378, 1854105484, 2746713774, 4003707568
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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J. Serra-Sagrista, Enumeration of lattice points in l_1 norm, Information Processing Letters, 76, no. 1-2 (2000), 39-44.
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LINKS
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J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (Abstract, pdf, ps).
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FORMULA
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a(n)= ( 4*n^9 +168*n^7 +1596*n^5 +3272*n^3 +630*n )/(5*7*9*9). - frank.ellermann(AT)t-online.de, Mar 16 2002
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MAPLE
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f := proc(d, m) local i; sum( 2^i*binomial(d, i)*binomial(m-1, i-1), i=1..min(d, m)); end; # n=dimension, m=norm
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CROSSREFS
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Cf. A035596 - A035607.
Sequence in context: A099903 A074426 A082636 this_sequence A126735 A119582 A157055
Adjacent sequences: A035600 A035601 A035602 this_sequence A035604 A035605 A035606
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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