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A080528 Sum of multinomials of (-1 +number of runs) in the partitions of n. 0
1, 2, 3, 5, 7, 12, 17, 28, 42, 68, 104, 171, 268, 442, 715, 1192, 1970, 3332, 5611, 9614, 16472, 28546, 49583, 86876, 152656, 269983, 479077, 854309, 1528314, 2745113, 4945015, 8937266 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Sum of multinomials of number of runs in the partitions of n equals 2^(n-1), so a(n) is less than 2^(n-1).

EXAMPLE

The partitions of 4: {4},{3,1},{2,2},{2,1,1},{1,1,1,1} have {1},{1,1},{2},{2,1},{4} runs of equal integers. The sum of the Multinomials of {0},{0,0},{1},{1,0},{3} equals 5.

MATHEMATICA

multiplicity2[li:{__Integer}] := (Multinomial@@(-1+Length/@Split[ # ]))&[Sort@li]; Table[Plus@@multiplicity2/@Partitions[n], {n, 32}]

CROSSREFS

Sequence in context: A060730 A123569 A048816 * A206788 A002965 A206290

Adjacent sequences:  A080525 A080526 A080527 * A080529 A080530 A080531

KEYWORD

easy,nonn

AUTHOR

Wouter Meeussen (wouter.meeussen(AT)pandora.be), Mar 22 2003

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Last modified February 17 21:13 EST 2012. Contains 206085 sequences.