OFFSET
0,2
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 and Brian Freidin, On the proportion of transverse-free plane curves, arXiv:2009.13421 [math.AG], 2020.
Zeynelabidin Karakaş, Classification of Distinct Maximal Flag Codes of a Prescriped Type and Related Results, PhD Thesis, Middle East Technical University, 2023. See pages 40 and 43.
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,changed
AUTHOR
EXTENSIONS
a(5) from Georg Muntingh, Feb 03 2014
Offset corrected, definition clarified, and a(6)=0 added by Max Alekseyev, Nov 15 2025
STATUS
approved
