a(n) = 4*(16^n-1)/15.
A141032
a(n) = 4*(16^n-1)/15.
Terms
- a(0) =0a(1) =4a(2) =68a(3) =1092a(4) =17476a(5) =279620a(6) =4473924a(7) =71582788a(8) =1145324612a(9) =18325193796a(10) =293203100740
External references
- oeis: A141032
A141032
a(n) = 4*(16^n-1)/15.