225684

Appears in sequences

• a(n) = Sum_{k=0..n} binomial(n, floor(k/2))*3^(n-k).at n=10A127359
• Triangular array read by rows: T(n,k) is the number of ordered set partitions of {1,2,...,n} with exactly k singletons, n>=0, 0<=k<=n.at n=46A187784