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A026837 Number of partitions of n into distinct parts, the greatest being odd. +0
6
1, 0, 1, 1, 2, 2, 2, 3, 4, 5, 6, 8, 9, 11, 13, 16, 19, 23, 27, 32, 38, 45, 52, 61, 71, 82, 96, 111, 128, 148, 170, 195, 224, 256, 293, 334, 380, 432, 491, 556, 630, 713, 805, 908, 1024, 1152, 1295, 1455, 1632, 1829, 2049, 2291, 2560, 2859 (list; graph; listen)
OFFSET

1,5

COMMENT

Fine's theorem: A026838(n) - a(n) = 1 if n = k(3k+1)/2, = -1 if n = k(3k-1)/2, = 0 otherwise.

Also number of partitions of n into an odd number of parts and such that parts of every size from 1 to the largest occur. Example: a(9)=4 because we have [3,2,2,1,1],[2,2,2,2,1],[2,2,1,1,1,1,1], and [1,1,1,1,1,1,1,1,1]. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 04 2006

REFERENCES

I. Pak, On Fine's partition theorems, Dyson, Andrews, and missed opportunities, Math. Intelligencer, 25 (No. 1, 2003), 10-16.

FORMULA

G.f.=sum(x^(2k-1)*product(1+x^j, j=1..2k-2), k=1..infinity). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 04 2006

a(2*n)=A118302(2*n), a(2*n-1)=A118301(2*n-1); a(n)=A000009(n)-A026838(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Apr 22 2006

EXAMPLE

a(9)=4 because we have [9],[7,2],[5,4], and [5,3,1].

MAPLE

g:=sum(x^(2*k-1)*product(1+x^j, j=1..2*k-2), k=1..40): gser:=series(g, x=0, 60): seq(coeff(g, x, n), n=1..54); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 04 2006

CROSSREFS

Cf. A026838.

Cf. A027193.

Sequence in context: A018121 A111212 A102240 this_sequence A005855 A096748 A022866

Adjacent sequences: A026834 A026835 A026836 this_sequence A026838 A026839 A026840

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu)

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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