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A052546
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Expansion of (1-x)/(1-x-x^2-2x^3+2x^4).
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1
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1, 0, 1, 3, 2, 7, 13, 18, 41, 71, 122, 239, 421, 762, 1417, 2543, 4642, 8495, 15389, 28082, 51177, 93047, 169610, 308847, 562197, 1024170, 1864841, 3395711, 6184498, 11261551, 20507789, 37346914, 68008809, 123848199, 225535258
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 482
Index to sequences with linear recurrences with constant coefficients, signature (1,1,2,-2)
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FORMULA
| G.f.: -(-1+x)/(1-x-2*x^3+2*x^4-x^2)
Recurrence: {a(1)=0, a(0)=1, a(2)=1, a(3)=3, 2*a(n)-2*a(n+1)-a(n+2)-a(n+3)+a(n+4)=0}
Sum(-1/353*(-18-106*_alpha+33*_alpha^2+28*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(1-_Z-2*_Z^3+2*_Z^4-_Z^2))
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MAPLE
| 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
| Sequence in context: A053440 A143332 A114647 * A049968 A049970 A104528
Adjacent sequences: A052543 A052544 A052545 * A052547 A052548 A052549
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jun 06 2000
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