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A000987
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Number of stochastic matrices of integers.
(Formerly M1793 N0707)
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1
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0, 1, 1, 2, 7, 32, 184, 1268, 10186, 93356, 960646, 10959452, 137221954, 1870087808, 27548231008, 436081302248, 7380628161076, 132975267434552, 2540593483517404, 51299775805464824, 1091447620966600804, 24401984084483685248, 571907754141520643296
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OFFSET
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0,4
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REFERENCES
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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
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FORMULA
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MATHEMATICA
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(* b = A000985 *) Clear[a, b]; b[0] = 1; b[1] = 1; b[2] = 3; b[3] = 11; b[4] = 56; b[n_] := b[n] = (2*n-1)*b[n-1] - (n-2)*(n-1)*b[n-2] - (n-2)*(n - 1)*b[n-3] + (n-3)*(n-2)*(n-1)*b[(n-4)]/2; a[0] = 0; a[1] = 1; a[n_] := a[n] = (n-2)*a[n-1] + b[n-2]; Array[a, 22, 0] (* Jean-François Alcover, Feb 15 2016, after Sean A. Irvine *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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