

A309984


Number of n X n Latin squares with determinant 0, divided by 2.


3




OFFSET

1,4


LINKS

Table of n, a(n) for n=1..8.
Brendan McKay, Latin squares.
Hugo Pfoertner, Occurrence counts of determinant values of Latin squares for n=1..8, zipped (2019).


EXAMPLE

a(4)=16: There are 2*a(4) = 32 4 X 4 Latin squares with determinant = 0, one of which is
[1 4 3 2]
[4 1 2 3]
[3 2 1 4]
[2 3 4 1].
An example of a 6 X 6 Latin square with determinant = 0 is
[1 3 4 6 5 2]
[3 2 6 5 4 1]
[4 6 3 2 1 5]
[6 5 1 3 2 4]
[5 4 2 1 3 6]
[2 1 5 4 6 3].


CROSSREFS

Cf. A040082, A136609, A221976, A301371, A308853, A309258, A309985.
Sequence in context: A221380 A221759 A111979 * A173436 A081263 A265491
Adjacent sequences: A309981 A309982 A309983 * A309985 A309986 A309987


KEYWORD

nonn,more,hard


AUTHOR

Hugo Pfoertner, Aug 26 2019


STATUS

approved



