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Search: id:A001046
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| A001046 |
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a(n) = n(n-1)a(n-1)/2 + a(n-2).
(Formerly M1811 N0717)
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+0
1
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| 1, 1, 2, 7, 44, 447, 6749, 142176, 3987677, 143698548, 6470422337, 356016927083, 23503587609815, 1833635850492653, 166884365982441238, 17524692064006822643, 2103129932046801158398, 286043195450428964364771
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
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EXAMPLE
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a(4) = 4*3*7/2 + 2 = 44.
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CROSSREFS
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Cf. A001052.
Sequence in context: A000155 A077045 A128579 this_sequence A158257 A153522 A107354
Adjacent sequences: A001043 A001044 A001045 this_sequence A001047 A001048 A001049
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Oct 05 2000
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