OFFSET
1,2
COMMENTS
Numbers n such that A253236(n) = 0.
Numbers n such that all divisors of Phi_n(b) are congruent to 1 (mod n) for every natural number b.
If p is prime, k, r are natural numbers, then:
Every n = p^r is not in this sequence.
Every n = 2p^r is not in this sequence.
n = 3p^r (p>3) is in this sequence iff p != 1 (mod 3).
n = 4p^r (p>4) is in this sequence iff p != 1 (mod 4).
n = 5p^r (p>5) is in this sequence iff p != 1 (mod 5).
...
n = kp^r (p>k) is in this sequence iff p != 1 (mod k).
LINKS
Eric Chen and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1000 terms from Chen)
PROG
(PARI) is(n)=my(P=polcyclo(n), f=factor(n)[, 1]); for(i=1, #f, if(#polrootsmod(P, f[i]), return(0))); 1 \\ Charles R Greathouse IV, Apr 20 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric Chen, Apr 19 2015
STATUS
approved