127035domain: NAppears in sequencesNumber of nX3 0..1 arrays with every element equal to 0, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.at n=16A298439a(n) = Sum_{k=1..n} k^2*phi(k), where phi is the Euler totient function A000010.at n=29A319087