959224domain: NAppears in sequencesNumber 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, 0), (0, 0, -1), (1, 0, 1), (1, 1, 0)}.at n=10A150735a(n) = Sum_{k=1..n} tan(k*Pi/(1+2*n))^4.at n=24A377858