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Search: id:A052537
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| A052537 |
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A simple regular expression. |
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+0
4
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| 1, 0, 0, 2, 2, 2, 6, 10, 14, 26, 46, 74, 126, 218, 366, 618, 1054, 1786, 3022, 5130, 8702, 14746, 25006, 42410, 71902, 121914, 206734, 350538, 594366, 1007834, 1708910, 2897642, 4913310, 8331130, 14126414, 23953034, 40615294, 68868122, 116774190
(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 468
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FORMULA
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G.f.: (-1+x)/(-1+x+2*x^3)
Recurrence: {a(1)=0, a(0)=1, a(2)=0, 2*a(n)+a(n+2)-a(n+3)}
Sum(-1/29*(1+3*_alpha^2-10*_alpha)*_alpha^(-1-n), _alpha=RootOf(-1+_Z+2*_Z^3))
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MAPLE
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spec := [S, {S=Sequence(Prod(Z, Z, Union(Z, Z), Sequence(Z)))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Cf. A003229.
Adjacent sequences: A052534 A052535 A052536 this_sequence A052538 A052539 A052540
Sequence in context: A121698 A087482 A137227 this_sequence A024945 A032306 A058756
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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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