311809domain: NAppears in sequencesNumber of n X 4 0..1 arrays with each 1 adjacent to 3 or 6 king-move neighboring 1s.at n=19A296309a(n) = numerator of Sum_{1 <= i < j <= d(n)} 1/(d_j - d_i), sum over ordered pairs of divisors of n, where d(n) is the number of divisors of n.at n=27A330077