2204416

Appears in sequences

• Number 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, 0), (-1, 1, -1), (0, 1, 1), (1, -1, 0), (1, 0, 1)}.at n=11A150240
• a(n) = Sum_{k=0..n} 2^k*(n!/k!)^2.at n=6A228513