a(n) = 27^n * Sum_{k=0..n} (-1)^k*binomial(-1/3, k)^2.

A367330

a(n) = 27^n * Sum_{k=0..n} (-1)^k*binomial(-1/3, k)^2.

Terms

    a(0) =1a(1) =24a(2) =684a(3) =17880a(4) =493785a(5) =13108608a(6) =358702272a(7) =9579537792a(8) =261039317220

External references