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A035611
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Coordination sequence for lattice D*_22 (with edges defined by l_1 norm = 1).
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0
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1, 44, 968, 14212, 156816, 1388508, 10286936, 65652532, 368804128, 1854105484, 8453107432, 35333619428, 136677756336, 493244610364, 1672424817272, 5360494538388, 16327295550016, 47469373288172, 132235461020168, 354093052356164, 913949931165392, 2279318877511324, 5504063080258968, 12893712963761652
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OFFSET
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0,2
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LINKS
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Index entries for linear recurrences with constant coefficients, signature (22, -231, 1540, -7315, 26334, -74613, 170544, -319770, 497420, -646646, 705432, -646646, 497420, -319770, 170544, -74613, 26334, -7315, 1540, -231, 22, -1).
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FORMULA
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a(m) = add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n)+2^n*binomial((n+2*m)/2-1, n-1); with n=22.
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MAPLE
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C := (m, n) -> `if`(m=0, 1, 2^n*binomial((n+2*m)/2-1, n-1) + 2*n*hypergeom([1-m, 1-n], [2], 2)): seq(simplify(C(m, 22)), m=0..21); # Peter Luschny, Jul 18 2020
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MATHEMATICA
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n:=22; Table[Sum[2^k*Binomial[n, k]*Binomial[m-1, k-1], {k, 0, n}] + 2^n*Binomial[(n+2*m)/2-1, n-1], {m, 0, n+2}] (* Georg Fischer, Jul 18 2020 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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