Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%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