Number of n X n binary arrays, symmetric under 90-degree rotation, 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.
A144243
Number of n X n binary arrays, symmetric under 90-degree rotation, 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.
Terms
- a(0) =1a(1) =2a(2) =1a(3) =3a(4) =2a(5) =10a(6) =36a(7) =77a(8) =170a(9) =1539a(10) =2778a(11) =26239a(12) =152082a(13) =1317122a(14) =7797811a(15) =129473317a(16) =857792500a(17) =17986500145a(18) =205469564882
External references
- oeis: A144243