A245973 Tower of 6s mod n.

0, 0, 0, 0, 1, 0, 1, 0, 0, 6, 5, 0, 1, 8, 6, 0, 1, 0, 1, 16, 15, 16, 2, 0, 6, 14, 0, 8, 23, 6, 1, 0, 27, 18, 1, 0, 1, 20, 27, 16, 18, 36, 1, 16, 36, 2, 36, 0, 43, 6, 18, 40, 47, 0, 16, 8, 39, 52, 9, 36, 9, 32, 36, 0, 1, 60, 14, 52, 48, 36, 6, 0, 1, 38, 6, 20

Offset: 1

Author

Wayne VanWeerthuizen, Aug 08 2014

Keywords

• nonn
• easy

Comments

a(n) = (6^(6^(6^(6^(6^ ... ))))) mod n, provided sufficient 6s are in the tower such that adding more doesn't affect the value of a(n).

Links

• Wayne VanWeerthuizen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A240162, A245970, A245971, A245972, A245974.

Programs

Sage

def tower6mod(n):
    if ( n <= 12 ):
        return 46656%n
    else:
        ep = euler_phi(n)
        return power_mod(6,ep+tower6mod(ep),n)