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A002874
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Sorting numbers.
(Formerly M1863 N0738)
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8
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1, 2, 8, 42, 268, 1994, 16852, 158778, 1644732, 18532810, 225256740, 2933174842, 40687193548, 598352302474, 9290859275060, 151779798262202, 2600663778494172, 46609915810749130, 871645673599372868
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| T. S. Motzkin, Sorting numbers ...: for a link to this paper see A000262.
T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| T. D. Noe, Table of n, a(n) for n=0..100
Index entries for sequences related to sorting
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FORMULA
| E.g.f.: exp (( exp(3*x) - 4) / 3 + exp(x) ).
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MATHEMATICA
| u[0, j_]:=1; u[k_, j_]:=u[k, j]=Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 3], {n, 0, 12}] [From Wouter Meeussen (wouter.meeussen(AT)pandora.be), Dec 06 2008]
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CROSSREFS
| u[n,j] generates for j=1, A000110 Bell numbers; j=2, A002872 "Sorting numbers"; j=3, A002874 "Sorting numbers"; j=4, A141003 (Mathar); j=5, A036075 "Sorting numbers"; j=6, A141004 (Mathar); j=7, A036077 "Sorting numbers" [From Wouter Meeussen (wouter.meeussen(AT)pandora.be), Dec 06 2008]
Sequence in context: A188912 A005315 A121635 * A078592 A052646 A002856
Adjacent sequences: A002871 A002872 A002873 * A002875 A002876 A002877
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe (simon.plouffe(AT)gmail.com)
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