517621domain: NAppears in sequencesa(1)=3; a(2n), a(2n+1) are smallest integers > a(2n-1) such that a(2n-1)^2+a(2n)^2=a(2n+1)^2.at n=22A077034Number 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, 0, 1), (0, 1, -1), (1, -1, 0), (1, 0, 0)}.at n=13A148112