Number of n X n binary arrays, symmetric under horizontal and vertical reflection, 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.
A144238
Number of n X n binary arrays, symmetric under horizontal and vertical reflection, 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) =6a(6) =14a(7) =111a(8) =56a(9) =1337a(10) =718a(11) =24951a(12) =27864a(13) =1478458a(14) =1080087a(15) =130135921a(16) =85888038a(17) =18349790023a(18) =15914995870
External references
- oeis: A144238