a(n) = 3^(n*(n-1)/2) + 3^(n*(n+1)/2) for n > 0, with a(0) = 1.

A337969

a(n) = 3^(n*(n-1)/2) + 3^(n*(n+1)/2) for n > 0, with a(0) = 1.

Terms

    a(0) =1a(1) =4a(2) =30a(3) =756a(4) =59778a(5) =14407956a(6) =10474702110

External references