Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 10000-11100-00111-00001 pattern in any orientation.
A147380
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 10000-11100-00111-00001 pattern in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =3a(11) =7a(12) =13a(13) =23a(14) =55a(15) =135a(16) =325a(17) =777a(18) =2227a(19) =6637a(20) =24107a(21) =84917a(22) =344887a(23) =1418553a(24) =6697895
External references
- oeis: A147380