OFFSET
1,2
COMMENTS
Sequence is a permutation of the positive integers.
LINKS
James C. McMahon, Table of n, a(n) for n = 1..1000
EXAMPLE
6 has 4 positive divisors. Among those positive integers not occurring among the first 5 terms of the sequence, 9 is the smallest which is coprime to 4. So a(6) = 9. 4, 6 and 8 also do not occur among the first 5 terms of the sequence, but they are not coprime to 4.
MATHEMATICA
s={1}; Do[i=1; Until[!MemberQ[s, i]&&CoprimeQ[i, DivisorSigma[0, n]], i++]; AppendTo[s, i], {n, 2, 68}]; s (* James C. McMahon, Oct 12 2024 *)
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Leroy Quet, Aug 18 2006
EXTENSIONS
Extended by Ray Chandler, Aug 22 2006
STATUS
approved