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Search: id:A008414
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| A008414 |
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Coordination sequence for 6-dimensional cubic lattice. |
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+0
3
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| 1, 12, 72, 292, 912, 2364, 5336, 10836, 20256, 35436, 58728, 93060, 142000, 209820, 301560, 423092, 581184, 783564, 1038984, 1357284, 1749456, 2227708, 2805528, 3497748, 4320608, 5291820, 6430632
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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If Y_i (i=1,2,3,4,5,6) are 2-blocks of a (n+6)-set X then a(n-5) is the number of 11-subsets of X intersecting each Y_i (i=1,2,3,4,5,6). - Milan R. Janjic (agnus(AT)blic.net), Oct 28 2007
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LINKS
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Milan Janjic, Two Enumerative Functions
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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G.f.: ((1+x)/(1-x))^6.
a(n) = 4*n*(2/15*n^4+4/3*n^2+23/15). - S. Bujnowski (slawb(AT)atr.bydgoszcz.pl), Nov 26 2002
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MAPLE
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for n from 1 to 8 do eval(4*n*(2/15*n^4+4/3*n^2+23/15)) od;
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CROSSREFS
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Sequence in context: A047928 A008533 A010024 this_sequence A052181 A118979 A014970
Adjacent sequences: A008411 A008412 A008413 this_sequence A008415 A008416 A008417
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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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