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Search: id:A052916
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| A052916 |
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A simple regular expression. |
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+0
1
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| 1, 0, 0, 2, 1, 1, 5, 5, 6, 15, 20, 27, 51, 76, 110, 185, 286, 430, 690, 1077, 1651, 2601, 4065, 6290, 9841, 15370, 23885, 37277, 58176, 90576, 141245, 220320, 343296, 535210, 834605, 1300877, 2028001, 3162001, 4929150, 7684275, 11980276
(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 899
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FORMULA
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G.f.: -(-1+x)/(1-x-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+3)+a(n+4)}
Sum(-1/643*(13-201*_alpha+38*_alpha^2+18*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(1-_Z-2*_Z^3+_Z^4))
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MAPLE
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spec := [S, {S=Sequence(Prod(Z, Z, Union(Prod(Sequence(Z), Z), Z)))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A156045 A119687 A086856 this_sequence A156576 A092437 A064814
Adjacent sequences: A052913 A052914 A052915 this_sequence A052917 A052918 A052919
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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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