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Search: id:A068199
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| A068199 |
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One of a family of sequences that interpolates between the Bell numbers and the factorials. |
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+0
4
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| 1, 2, 6, 24, 114, 618, 3732, 24702, 177126, 1363740, 11195286, 97437138, 894857712, 8637708858, 87333790686, 922203924216, 10144109299146, 115972625504994, 1375221840671220, 16884112119546534, 214270296662325534
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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G. Labelle et al., Stirling numbers interpolation using permutations with forbidden subsequences, Discrete Math. 246 (2002), 177-195.
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FORMULA
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E.g.f.: 1 + 2exp(3exp(x)-3).
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MAPLE
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g:= proc(n) option remember; `if` (n=0, 1, (1+add (binomial (n-1, k-1) *g(n-k), k=1..n-1)) *3) end: a:= n-> `if`(n=0, 1, 2*g(n-1)): seq (a(n), n=0..25); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 09 2008]
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CROSSREFS
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Cf. A000110, A001861, this, A068200, A068201, ..., A000142.
Equals 2 * A027710(n).
Sequence in context: A152329 A054872 A134664 this_sequence A128088 A069657 A082631
Adjacent sequences: A068196 A068197 A068198 this_sequence A068200 A068201 A068202
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Mar 23 2002
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EXTENSIONS
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More terms from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 09 2008
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