74186domain: NAppears in sequencesDenominators of continued fraction convergents to sqrt(409).at n=10A041777Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 01010-11111 pattern in any orientation.at n=18A147063a(n) = 2*n^3 - 4*n^2 + 6*n - 2 (n>=1).at n=33A304159