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A052946
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Expansion of (1-x)^2/(1-3x+2x^3-x^4).
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1
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1, 1, 4, 10, 29, 80, 224, 624, 1741, 4855, 13541, 37765, 105326, 293751, 819264, 2284905, 6372539, 17772840, 49567974, 138243749, 385558106, 1075311210, 2999014106, 8364169855, 23327445251, 65059618751, 181449530649
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 1005
Index to sequences with linear recurrences with constant coefficients, signature (3,0,-2,1).
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FORMULA
| G.f.: -(-1+x)^2/(-1+3*x-2*x^3+x^4)
Recurrence: {a(1)=1, a(0)=1, a(2)=4, a(n)-2*a(n+1)+3*a(n+3)-a(n+4)=0, a(3)=10}
Sum(1/643*(79+128*_alpha-133*_alpha^2+40*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(-1+3*_Z-2*_Z^3+_Z^4))
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MAPLE
| spec := [S, {S=Sequence(Prod(Union(Prod(Sequence(Z), Sequence(Z)), Z), Z))}, unlabeled ]: seq(combstruct[count ](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A111236 A164361 A006907 * A026152 A025179 A116388
Adjacent sequences: A052943 A052944 A052945 * A052947 A052948 A052949
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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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