21096027

Appears in sequences

• a(n) = C(n-2,2)+C(n-5,5)+...+C(n-(3*floor((n-3)/3)+2),3*floor((n-3)/3)+2).at n=38A101551
• Lower level digraph derived from a voltage graph.at n=39A115055
• a(n) = Sum_{k=0..floor(2*n/3)} binomial(3*k,2*n-3*k).at n=19A392432