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A052543
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Expansion of (1-x/(1-3x-2x^2+2x^3).
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1
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1, 2, 8, 26, 90, 306, 1046, 3570, 12190, 41618, 142094, 485138, 1656366, 5655186, 19308014, 65921682, 225070702, 768439442, 2623616366, 8957586578, 30583113582, 104417281170, 356502897518, 1217177027730, 4155702315886
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 478
Index to sequences with linear recurrences with constant coefficients, signature (3,2,-2).
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FORMULA
| G.f.: -(-1+x)/(1-3*x-2*x^2+2*x^3)
Recurrence: {a(0)=1, a(1)=2, a(2)=8, 2*a(n)-2*a(n+1)-3*a(n+2)+a(n+3)}
Sum(-1/98*(-13-25*_alpha+16*_alpha^2)*_alpha^(-1-n), _alpha=RootOf(1-3*_Z-2*_Z^2+2*_Z^3))
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MAPLE
| spec := [S, {S=Sequence(Prod(Union(Z, Z), Union(Z, Sequence(Z))))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A060410 A128634 A053956 * A026638 A067855 A129368
Adjacent sequences: A052540 A052541 A052542 * A052544 A052545 A052546
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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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