Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in two by two blocks.
A145862
Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in two by two blocks.
Terms
- a(0) =1a(1) =2a(2) =1a(3) =2a(4) =2a(5) =5a(6) =3a(7) =12a(8) =6a(9) =32a(10) =16a(11) =104a(12) =49a(13) =441a(14) =169a(15) =2087a(16) =742a(17) =12047a(18) =3848a(19) =83725a(20) =23784a(21) =695140a(22) =176890a(23) =6907583a(24) =1574720a(25) =82485542a(26) =16764539a(27) =1176502867a(28) =214487123a(29) =20130478473
External references
- oeis: A145862