OFFSET
1,1
COMMENTS
From Bernard Schott, Mar 29 2021: (Start)
The first such pairs (m, q) in lexicographic order are (8, 9), (25, 32), (49, 128), (121, 2048), (125, 243), (169, 8192), (200, 288), (289, 131072), ...
If f = A008477, terms k of this sequence are precisely the ones for which the sequence k, f(k), f(f(k)), f(f(f(k))), ... is periodic with period = 2 (see 1st comment in A008477); example for k = 8, this periodic sequence is 8, 9, 8, 9, 8, 9, ...
Prime powers p^r, p, r primes, p <> r are terms. (End)
LINKS
Michel Marcus, Table of n, a(n) for n = 1..4336
EXAMPLE
PROG
(PARI) f(n) = factorback(factor(n)*[0, 1; 1, 0]); \\ A008477
isok(m) = my(nm = f(m)); (nm != m) && (f(nm) == m); \\ Michel Marcus, Mar 29 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Naohiro Nomoto, Mar 28 2002
STATUS
approved