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A103421 Number of compositions of n in which the greatest part is odd. 2
1, 1, 2, 3, 7, 14, 30, 62, 129, 263, 534, 1076, 2160, 4318, 8612, 17145, 34097, 67764, 134638, 267506, 531606, 1056812, 2101854, 4182462, 8327263, 16588973, 33066080, 65945522, 131588128, 262702054, 524699094, 1048433468, 2095744336 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..33.

FORMULA

G.f.: Sum((1-x)^2*x^(2*n-1)/((1-2*x+x^(2*n-1))*(1-2*x+x^(2*n))), n=1..infinity).

a(n) + A103422(n) = 2^(n-1). - R. J. Mathar, Mar 24 2018

MATHEMATICA

Rest[ CoefficientList[ Series[ Expand[ Sum[(1 - x)^2*x^(2n - 1)/((1 - 2x + x^(2n - 1))*(1 - 2x + x^(2n))), {n, 35}]], {x, 0, 35}], x]] (* Robert G. Wilson v, Feb 05 2005 *)

CROSSREFS

Cf. A103419, A103420, A103422, A027187, A027193, A026804, A026805.

Sequence in context: A192570 A019595 A112884 * A205484 A151530 A180752

Adjacent sequences:  A103418 A103419 A103420 * A103422 A103423 A103424

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Feb 04 2005

EXTENSIONS

More terms from Robert G. Wilson v, Feb 05 2005

STATUS

approved

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Last modified October 21 19:16 EDT 2021. Contains 348155 sequences. (Running on oeis4.)