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A105205
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G.f.: Sum((1-x)^(2*l)*Sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l),k=1..infinity),l=1..infinity).
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1, 1, 4, 6, 13, 24, 51, 101, 205, 407, 814, 1624, 3248, 6490, 12979, 25950, 51898, 103798, 207619, 415288, 830690, 1661590, 3323566, 6647779, 13296602, 26594769, 53191708, 106386020, 212774300, 425548246, 851088094, 1702147791, 3404222451
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| Number of compositions of n such that the greatest part occurs with odd multiplicity.
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EXAMPLE
| a(4)=6 because we have (4),(3,1),(1,3),(2,1,1),(1,2,1) and (1,1,2).
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MAPLE
| G:=sum((1-x)^(2*l)*sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l), k=1..30), l=1..20): Gser:=series(G, x=0, 35): seq(coeff(Gser, x^n), n=1..33); (Deutsch)
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CROSSREFS
| Cf. A105201, A105200.
Sequence in context: A120463 A049732 A136391 * A160805 A012776 A016072
Adjacent sequences: A105202 A105203 A105204 * A105206 A105207 A105208
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KEYWORD
| easy,nonn
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 12 2005
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 07 2005
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