-9565938

Appears in sequences

• a(n) = Sum_{j=0..floor(n/3)} (-1)^j*binomial(n,3*j).at n=30A057681
• A transform of the Jacobsthal numbers.at n=31A103312
• Inverse binomial transform of A169609, or of A144437 preceded by 1.at n=29A168615