321640831

Appears in sequences

• a(n) = Sum_{k=0..floor(n/4)} C(n-2*k,2*k) * 3^k.at n=32A098576
• a(n) = Sum_{k=0..floor(n/2)} binomial(2n-2k,2k) * 3^(n-k).at n=16A108484