1,1

There are no primes of the form A174881(k)-1.

There are no further terms through ((40*(40+1))^40) + 1 = 52330005981567385600000001 * 7498996269037701079813541255115132352481561590213553612395236504891175431182405289081378432614400.

Contribution from Farideh Firoozbakht, Apr 22 2010: (Start)

Each term is of the form (4^n+2^n)^2^n+1. Next term (if it exists) is

greater than (4^15+2^15)^2^15, so it has more than 295924 digits. (End)

Table of n, a(n) for n=1..3.

a(1) = (1^1)*((1+1)^1) + 1 = 2 + 1 = 3 is prime.

a(2) = (2^2)*((2+1)^2) + 1 = 36 + 1 = 37 is prime.

a(3) = (4^4)*((4+1)^4) + 1 = 160000 + 1 = 160001 is prime.

Cf. A000040, A000169, A000312, A174881.

Sequence in context: A120480 A088098 A284411 * A122787 A241895 A093939

Adjacent sequences: A176242 A176243 A176244 * A176246 A176247 A176248

bref,more,nonn

Jonathan Vos Post, Apr 12 2010

Edited by Farideh Firoozbakht and N. J. A. Sloane, Apr 18 2010

approved