OFFSET
1,2
COMMENTS
The first four terms that are not powers of primes are: a(112) = 15, a(122) = 35, a(145) = 33, a(155) = 12.
Question: Are 2, 3, 4, 6, 10, 12, 18, 30, 60 the only n such that a(n) = 1+n?
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..3349 (computed using million term data file provided for A344005 by N. J. A. Sloane)
FORMULA
a(n) = A354931(n) / n.
MATHEMATICA
s[n_] := Module[{m = 1}, While[!Divisible[m*(m+1), n], m++]; GCD[n, m]]; a[n_] := Module[{k = n}, While[s[k] != n, k+=n]; k/n]; Array[a, 100] (* Amiram Eldar, Jun 15 2022 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 14 2022
STATUS
approved