312013

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), (-1, 1, -1), (-1, 1, 1), (1, 0, 0)}.at n=13A148070
• Place n equally spaced points on each side of a square, and join each of these points by a chord to the 3*n new points on the other three sides: sequence gives number of vertices in the resulting planar graph.at n=15A367276
• a(n) = Sum_{k=0..n} (-1)^k * (k+1) * binomial(4*n-3*k+1,n-k)/(4*n-3*k+1).at n=8A387982