21176

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, 1), (-1, 1, 1), (0, 0, 1), (1, 0, -1), (1, 0, 0)}.at n=8A150147
• Number of length n+7 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.at n=38A255998
• a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} binomial(n,k)^2 * k * 4^(k-1) * a(n-k).at n=5A337594