a(n) = (4^(2*n+1) + 1) / 5.
A299960
a(n) = (4^(2*n+1) + 1) / 5.
Terms
- a(0) =1a(1) =13a(2) =205a(3) =3277a(4) =52429a(5) =838861a(6) =13421773a(7) =214748365a(8) =3435973837a(9) =54975581389a(10) =879609302221
External references
- oeis: A299960
A299960
a(n) = (4^(2*n+1) + 1) / 5.