291115domain: NAppears in sequencesRelated to population of numbers of form x^2 + y^2.at n=20A000693Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 1), (1, 0, -1), (1, 0, 1), (1, 1, 0)}.at n=9A150791