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A035890 Coordination sequence for diamond structure D^+_28. (Edges defined by l_1 norm = 1.) 1
1, 0, 1568, 0, 410816, 0, 43381856, 0, 2485013888, 0, 90102925472, 0, 2275791199808, 0, 42760561395424, 3758096384, 627153507629824, 544923975680, 7450881715909408, 27028229193728, 73852826419374016 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
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.
Index entries for linear recurrences with constant coefficients, signature (0, 28, 0, -378, 0, 3276, 0, -20475, 0, 98280, 0, -376740, 0, 1184040, 0, -3108105, 0, 6906900, 0, -13123110, 0, 21474180, 0, -30421755, 0, 37442160, 0, -40116600, 0, 37442160, 0, -30421755, 0, 21474180, 0, -13123110, 0, 6906900, 0, -3108105, 0, 1184040, 0, -376740, 0, 98280, 0, -20475, 0, 3276, 0, -378, 0, 28, 0, -1).
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=28.
CROSSREFS
Sequence in context: A237673 A246734 A237467 * A252109 A045276 A099542
KEYWORD
nonn
AUTHOR
Joan Serra-Sagrista (jserra(AT)ccd.uab.es)
EXTENSIONS
Recomputed by N. J. A. Sloane, Nov 27 1998
STATUS
approved

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)