A144240 Number of n X n binary arrays, symmetric about both diagonal and antidiagonal, with every 1 adjacent to at least one other 1 both bishopwise and rookwise but with no three 1s in a row bishopwise or rookwise.

1, 2, 1, 5, 4, 10, 32, 89, 174, 2023, 3612, 30003, 170438, 1387640, 7339317, 153956133, 877660696, 18345445123, 211690980458, 5237531076262

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Crossrefs

Sequence in context: A019473 A056605 A091802 * A233525 A209143 A243274

Adjacent sequences: A144237 A144238 A144239 * A144241 A144242 A144243

Keyword

nonn

Author

R. H. Hardin, Sep 15 2008

Status

approved