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5, 56, 263, 815, 1982, 4115, 7646, 13088, 21035, 32162, 47225, 67061, 92588, 124805, 164792, 213710, 272801, 343388, 426875, 524747, 638570, 769991, 920738, 1092620, 1287527, 1507430, 1754381, 2030513, 2338040, 2679257, 3056540
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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REFERENCES
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I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983,(2.3.14).
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LINKS
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Table of n, a(n) for n=0..30.
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FORMULA
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G.f.: (5+33*x^2+10*x^3+31*x+2*x^4)/(1-x)^5. Generally, g.f. for k-th column of A046741 is coefficient of y^k in expansion of (1-y)/((1-y-y^2)*(1-y)-(1+y)*x).
a(0)=5, a(1)=56, a(2)=263, a(3)=815, a(4)=1982, a(n)=5*a(n-1)- 10*a(n-2)+ 10*a(n-3)-5*a(n-4)+a(n-5) [From Harvey P. Dale, Dec 21 2011]
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MATHEMATICA
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LinearRecurrence[{5, -10, 10, -5, 1}, {5, 56, 263, 815, 1982}, 31] (* or *) CoefficientList[Series[(5+33x^2+10x^3+31x+2x^4)/(1-x)^5, {x, 0, 30}], x] (* From Harvey P. Dale, Dec 21 2011 *)
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CROSSREFS
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Cf. dumbbells: A002940, A002941, A002889, A046741, A055608, A062123-A062127.
Sequence in context: A072318 A174514 A041995 * A030060 A174249 A073563
Adjacent sequences: A062122 A062123 A062124 * A062126 A062127 A062128
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic, Jun 04 2001
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EXTENSIONS
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More terms from Larry Reeves (larryr(AT)acm.org), Jun 06 2001
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STATUS
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approved
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