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%I M1793 N0707 #32 May 24 2017 08:34:15
%S 0,1,1,2,7,32,184,1268,10186,93356,960646,10959452,137221954,
%T 1870087808,27548231008,436081302248,7380628161076,132975267434552,
%U 2540593483517404,51299775805464824,1091447620966600804,24401984084483685248,571907754141520643296
%N Number of stochastic matrices of integers.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H John Cerkan, <a href="/A000987/b000987.txt">Table of n, a(n) for n = 0..445</a>
%H H. Gupta, <a href="http://dx.doi.org/10.1215/S0012-7094-68-03567-9">Enumeration of symmetric matrices</a>, Duke Math. J., 35 (1968), vol 3, 653-659.
%H H. Gupta, <a href="/A000085/a000085.pdf">Enumeration of symmetric matrices</a> (annotated scanned copy).
%F a(0) = 0, a(1) = 1, a(n) = (n-2) * a(n-1) + A000985(n - 2), n >= 2. - _Sean A. Irvine_, Sep 24 2015
%t (* 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_ *)
%K nonn
%O 0,4
%A _N. J. A. Sloane_
%E More terms from _Sean A. Irvine_, Sep 24 2015
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