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Search: id:A052922
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| A052922 |
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A simple regular expression. |
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+0
1
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| 1, 0, 0, 2, 1, 0, 4, 4, 1, 8, 12, 6, 17, 32, 24, 40, 81, 80, 104, 202, 241, 288, 508, 684, 817, 1304, 1876, 2318, 3425, 5056, 6512, 9168, 13537, 18080, 24848, 36242, 49697, 67776, 97332, 135636, 185249, 262440, 368604, 506134, 710129, 999648, 1380872
(list; graph; listen)
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OFFSET
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0,4
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 907
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FORMULA
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G.f.: -1/(-1+2*x^3+x^4)
Recurrence: {a(1)=0, a(0)=1, a(2)=0, a(3)=2, a(n)+2*a(n+1)-a(n+4)}
Sum(-1/86*(-4-26*_alpha+3*_alpha^2+6*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(-1+2*_Z^3+_Z^4))
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MAPLE
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spec := [S, {S=Sequence(Prod(Z, Z, Union(Z, Z, Prod(Z, Z))))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A158454 A049243 A077908 this_sequence A109167 A066426 A100887
Adjacent sequences: A052919 A052920 A052921 this_sequence A052923 A052924 A052925
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KEYWORD
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easy,nonn
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AUTHOR
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encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jun 05 2000
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