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A001052
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a(n) = n(n-1)a(n-1)/2 + a(n-2).
(Formerly M0911 N0343)
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1
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1, 2, 3, 11, 69, 701, 10584, 222965, 6253604, 225352709, 10147125509, 558317255704, 36859086001973, 2875567025409598, 261713458398275391, 27482788698844325653, 3298196357319717353751, 448582187384180404435789
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| 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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PROG
| (PARI) a(n)=if(n<2, max(0, n+1), n*(n-1)*a(n-1)/2+a(n-2))
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CROSSREFS
| Sequence in context: A105217 A066046 A065597 * A184310 A155187 A109132
Adjacent sequences: A001049 A001050 A001051 * A001053 A001054 A001055
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Sep 19 2000
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