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.
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.
Terms
- a(0) =1a(1) =2a(2) =1a(3) =5a(4) =4a(5) =10a(6) =32a(7) =89a(8) =174a(9) =2023a(10) =3612a(11) =30003a(12) =170438a(13) =1387640a(14) =7339317a(15) =153956133a(16) =877660696a(17) =18345445123a(18) =211690980458
External references
- oeis: A144240