OFFSET
1,1
COMMENTS
A number k has a coprime divisor shift s if GCD(d + s, n) = 1 for all divisors d of k.
A number k has a coprime divisor shift iff it is not divisible by any number in the sequence.
If k has no coprime divisor shift, then so is any multiple of k.
REFERENCES
a(1) = 2 for GCD(2 + 0, 2) > 1 and GCD(1 + 1, 2) > 1.
a(2) = 15 for GCD(3 + 0, 15) > 1, GCD(5 + 1, 15) > 1, GCD(1 + 2, 15) > 1, and any odd number between 2 and 15 has a coprime divisor shift.
LINKS
M. Farrokhi D. G., Table of n, a(n) for n = 1..10000
CROSSREFS
KEYWORD
nonn
AUTHOR
M. Farrokhi D. G., Oct 07 2023
STATUS
approved