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A011966
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Third differences of Bell numbers.
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5
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1, 5, 20, 87, 409, 2066, 11155, 64077, 389946, 2504665, 16923381, 119928232, 888980293, 6876320041, 55382419676, 463539664643, 4024626253845, 36189297168874, 336513491259647, 3231446022478129, 32004743929977258, 326548129128737469, 3428663026172389201
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Number of partitions of n+4 with at least one singleton and with the smallest element in a singleton equal to 4. Alternatively, number of partitions of n+4 with at least one singleton and with the largest element in a singleton equal to n+1. - Olivier GERARD, Oct 29 2007
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REFERENCES
| Olivier Gerard and Karol A. Penson, A budget of set partition statistics, in preparation, unpublished as of Sep 22 2011.
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LINKS
| Alois P. Heinz, Table of n, a(n) for n = 0..215
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MAPLE
| a:= n-> add ((-1)^(k+1) *binomial(3, k) *combinat['bell'](n+k), k=0..3): seq (a(n), n=0..20); # Alois P. Heinz, Sep 05 2008
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MATHEMATICA
| Differences[BellB[Range[0, 30]], 3] (* From Harvey P. Dale, Apr 21 2011 *)
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CROSSREFS
| Cf. A000110.
Cf. A005493, A011965.
Sequence in context: A145932 A026661 A099014 * A192249 A017966 A196532
Adjacent sequences: A011963 A011964 A011965 * A011967 A011968 A011969
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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