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%I M2143 N2248 #33 Feb 01 2022 01:15:58
%S 1,2,24,3852,18534400,4598378639550
%N Permanent of projective plane of order n.
%D H. J. Ryser, Combinatorial Mathematics. Mathematical Association of America, Carus Mathematical Monograph 14, 1963, p. 124.
%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 Shamil Asgarli, Brian Freidin, <a href="https://arxiv.org/abs/2009.13421">On the proportion of transverse-free plane curves</a>, arXiv:2009.13421 [math.AG], 2020.
%H Georg Muntingh, <a href="/A000794/a000794.txt">Sage code for constructing the incidence matrix of the projective plane over a finite field of order n, and its permanent.</a>
%H Georg Muntingh, <a href="/A000794/a000794_2.txt">Incidence matrix of a projective plane over a finite field of order 2, 3, 4, 5, 7, 8, and 9</a>.
%H P. J. Nikolai, <a href="http://dx.doi.org/10.1090/S0025-5718-1960-0114764-0">Permanents of incidence matrices</a>, Math. Comp., 14 (1960), 262-266.
%e From _Georg Muntingh_, Feb 03 2014: (Start)
%e The projective plane over a finite field of order 2 has 7 points and 7 lines, for instance meeting with the incidence matrix
%e [1 0 0 1 1 0 0]
%e [0 1 1 0 1 0 0]
%e [1 0 1 0 0 1 0]
%e [0 1 0 1 0 1 0]
%e [0 0 1 1 0 0 1]
%e [1 1 0 0 0 0 1]
%e [0 0 0 0 1 1 1]
%e which has permanent 24. (End)
%K nonn,more
%O 1,2
%A _N. J. A. Sloane_
%E a(6) from _Georg Muntingh_, Feb 03 2014