a(n) = binomial(3*n,n)^2 - 27*binomial(2*n,n).
A357569
a(n) = binomial(3*n,n)^2 - 27*binomial(2*n,n).
Terms
- a(0) =-26a(1) =-45a(2) =63a(3) =6516a(4) =243135a(5) =9011205a(6) =344597148a(7) =13520945736a(8) =540917244351
External references
- oeis: A357569