A352801 Number of symmetric n X n 01-matrices with maximum number of 1s and no 2 X 2 all-1 submatrix.

1, 1, 2, 4, 16, 170, 360, 840, 82320, 181440, 1512000, 19958400, 79833600, 259459200, 14529715200

Offset

0,3

Links

Table of n, a(n) for n=0..14.

Formula

a(n) is the last element in the n-th row of triangle A350189.

Conjecture: the maximum number of 1s equals A072567(n), and so a(n) = A350189(n, A072567(n)).

Crossrefs

Cf. A072567, A191874, A191966, A335820, A350189, A351335, A352258.

Sequence in context: A202360 A050472 A109457 * A105788 A217727 A071008

Adjacent sequences: A352798 A352799 A352800 * A352802 A352803 A352804

Keyword

nonn,more

Author

Max Alekseyev, Apr 03 2022

Status

approved