A278771 Number of n X n 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly two mistakes.

0, 2, 266, 19750, 1673658, 251740932, 90752836672, 93037538287080, 293564184229043556, 2953569640505846392444

Offset

1,2

Comments

Diagonal of A278778.

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for n=4
..1..0..0..0. .0..0..0..0. .1..0..0..1. .1..1..0..0. .0..0..1..0
..1..1..0..1. .1..0..1..0. .1..1..1..1. .0..0..1..1. .1..0..0..0
..1..1..0..1. .0..0..0..0. .0..0..0..0. .0..0..1..0. .0..0..0..0
..1..0..0..0. .0..0..0..1. .1..1..1..0. .1..0..1..0. .0..0..1..1

Crossrefs

Cf. A278778.

Sequence in context: A135388 A238983 A188964 * A318171 A324596 A007512

Adjacent sequences: A278768 A278769 A278770 * A278772 A278773 A278774

Keyword

nonn

Author

R. H. Hardin, Nov 28 2016

Status

approved