69216domain: NAppears in sequencesNumber of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 7 king-move adjacent elements, with upper left element zero.at n=27A304225a(n) is the index of the first occurrence of the Euclidean distance prime(n) from a point on a square spiral to its starting point at 1.at n=36A336335