151497domain: NAppears in sequencesNumber of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1000-1111-0100 pattern in any orientation.at n=18A147119a(n) = 19683*n - 5967.at n=7A157669Numbers that are palindromic in bases 2 and 6.at n=17A182233