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Search: id:A079512
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| A079512 |
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a(0)=1, a(1)=1; for n>1, a(n) = Sum_{i=0..n/2} binomial(n-i-1,i)*a(n-2i-1) + ((n+1) mod 2). |
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+0
1
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| 1, 1, 2, 3, 6, 13, 29, 72, 185, 499, 1414, 4132, 12554, 39332, 126815, 420769, 1430790, 4986139, 17772536, 64708212, 240482750, 911008926, 3515571177, 13807269626, 55147622607, 223864614364, 922952281744, 3862571220690, 16399630000144
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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S. Kitaev, Multi-avoidance of generalized patterns, Discrete Math., 260 (2003), 89-100.
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MAPLE
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with(combinat): a := array(0..50): a[0] := 1: a[1] := 1: for n from 2 to 50 do: a[n] := 0: for i from 0 to floor((n-1)/2.) do: a[n] := a[n]+binomial(n-i-1, i)*a[n-2*i-1]: od:a[n] := a[n]+((n+1) mod 2): od:seq(a[n], n=0..50);
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MATHEMATICA
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a[0] = a[1] = 1; a[n_] := a[n] = Sum[ Binomial[n - i - 1, i]*a[n - 2i - 1], {i, 0, Floor[n/2]}] + Mod[n + 1, 2]; Table[a[n], {n, 0, 30}]
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CROSSREFS
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Sequence in context: A032066 A107316 A124682 this_sequence A052937 A005554 A077212
Adjacent sequences: A079509 A079510 A079511 this_sequence A079513 A079514 A079515
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KEYWORD
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easy,nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jan 21 2003
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EXTENSIONS
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More terms from Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 22 2003
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