a(n) = 4^n*(4^n - 1)/2.
A026337
a(n) = 4^n*(4^n - 1)/2.
Terms
- a(0) =0a(1) =6a(2) =120a(3) =2016a(4) =32640a(5) =523776a(6) =8386560a(7) =134209536a(8) =2147450880a(9) =34359607296a(10) =549755289600
External references
- oeis: A026337
A026337
a(n) = 4^n*(4^n - 1)/2.