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A097976
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Sum of largest parts (counted with multiplicity) in all compositions of n.
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0
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1, 4, 10, 24, 53, 118, 253, 542, 1143, 2396, 4986, 10330, 21304, 43808, 89837, 183838, 375514, 765880, 1559979, 3173794, 6450514, 13098246, 26574968, 53877266, 109153818, 221002456, 447199458, 904420716, 1828192748, 3693782678
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| G.f.: (1-x)^2*Sum(k*x^k/(1-2*x+x^(k+1))^2, k=1..infinity).
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EXAMPLE
| a(3)=10 because in the compositions111,12,21,3 the largest parts are 1,2,2,3 with multiplicities 3,1,1,1,respectively and 3*1+1*2+1*2+1*3=10.
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MAPLE
| G:=(1-x)^2*sum(k*x^k/(1-2*x+x^(k+1))^2, k=1..45): Gser:=series(G, x=0, 40): seq(coeff(Gser, x^n), n=1..35); (Deutsch)
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CROSSREFS
| Cf. A097940, A092321.
Sequence in context: A162588 A080615 A173729 * A152548 A090855 A052252
Adjacent sequences: A097973 A097974 A097975 * A097977 A097978 A097979
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KEYWORD
| easy,nonn
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 07 2004
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 28 2005
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