A372707 Smallest natural number requiring n applications of the map x -> 2^x mod x = A015910(x) to reach 0.

0, 1, 3, 18, 35, 207, 774, 1513, 2051, 8900, 13459, 25907, 34305, 88036, 153839, 382283, 397590, 636459, 844177, 1456073, 2426735, 7312307, 11716125, 14657311, 43165242, 52706549, 84955821, 188736643, 416569989, 953350161, 1617152961, 2541237149, 4847485412

Offset: 0

Author

Bryle Morga, May 11 2024

Keywords

• nonn

Comments

A015910 is conjectured to contain every natural number except for 1, which would imply that this sequence has infinitely many terms.

Links

• Kevin Ryde, Table of n, a(n) for n = 0..45
• Kevin Ryde, C Code

Crossrefs

Cf. A015910.

Programs

C

/* See links. */

Python

i = 0
c = [0]
for j in range(10**9):
    if c[-1] == i:
        print(f"a({i}) = {j}")
        i += 1
    c.append(1+c[pow(2, len(c), len(c))])

Extensions

a(30)-a(32) from Michael S. Branicky, May 12 2024