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A168585 Number of ways of partitioning the multiset {1,1,2,3,...,n-1} into exactly five nonempty parts. 3
1, 11, 90, 640, 4151, 25221, 146140, 817730, 4458201, 23835031, 125551790, 653873220, 3375658651, 17308994441, 88284419040, 448429907110, 2270331053501, 11464832543451, 57778226219890, 290711449879400 (list; graph; refs; listen; history; text; internal format)
OFFSET
5,2
LINKS
FORMULA
For a>=5, a(n) = (3*5^(n-2) - 10*4^(n-2) + 14*3^(n-2) - 3*2^(n) + 7)/24.
The shifted exponential generating function is (375e^(5x) - 640e^(4x) + 378e^(3x) - 96e^(2x) + 7e^x)/24.
The ordinary generating function is x^5(1-4x+10x^2)/((1-x)(1-2x)(1-3x)(1-4x)(1-5x)).
MATHEMATICA
f3[n_] := 1/24 (3 5^(n - 2) - 10 4^(n - 2) + 14 3^(n - 2) - 3 2^(n) + 7); Table[f3[n], {n, 3, 25}]
CROSSREFS
The number of ways of partitioning the multiset {1, 1, 2, 3, ..., n-1} into exactly two, three and four nonempty parts are given in A083329, A168583 and A168584, respectively.
Sequence in context: A110252 A199394 A171470 * A055425 A016212 A037713
KEYWORD
nonn,easy
AUTHOR
Martin Griffiths, Nov 30 2009
STATUS
approved

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Last modified February 26 03:53 EST 2024. Contains 370335 sequences. (Running on oeis4.)