a(n) = Sum_{k=0..n} 3^k * 2^(n-k) * binomial(3*n+1,k).

A386900

a(n) = Sum_{k=0..n} 3^k * 2^(n-k) * binomial(3*n+1,k).

Terms

    a(0) =1a(1) =14a(2) =235a(3) =4178a(4) =76495a(5) =1426184a(6) =26922076a(7) =512838410a(8) =9837067951a(9) =189729498350

External references