OFFSET
1,2
REFERENCES
H. J. Ryser, Combinatorial Mathematics. Mathematical Association of America, Carus Mathematical Monograph 14, 1963, p. 124.
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).
LINKS
Shamil Asgarli, Brian Freidin, On the proportion of transverse-free plane curves, arXiv:2009.13421 [math.AG], 2020.
Georg Muntingh, Sage code for constructing the incidence matrix of the projective plane over a finite field of order n, and its permanent.
Georg Muntingh, Incidence matrix of a projective plane over a finite field of order 2, 3, 4, 5, 7, 8, and 9.
P. J. Nikolai, Permanents of incidence matrices, Math. Comp., 14 (1960), 262-266.
EXAMPLE
From Georg Muntingh, Feb 03 2014: (Start)
The projective plane over a finite field of order 2 has 7 points and 7 lines, for instance meeting with the incidence matrix
[1 0 0 1 1 0 0]
[0 1 1 0 1 0 0]
[1 0 1 0 0 1 0]
[0 1 0 1 0 1 0]
[0 0 1 1 0 0 1]
[1 1 0 0 0 0 1]
[0 0 0 0 1 1 1]
which has permanent 24. (End)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
a(6) from Georg Muntingh, Feb 03 2014
STATUS
approved