OFFSET
1,2
COMMENTS
Conjecture: k always exists.
MATHEMATICA
seq[max_] := Module[{s = Table[0, {max}], c = 0, n = 1}, While[c < max, d = Denominator[DivisorSigma[1, n]/DivisorSigma[0, n]]; If[d <= max && s[[d]] == 0, c++; s[[d]] = n]; n++]; s]; seq[22] (* Amiram Eldar, Jul 26 2021 *)
PROG
(PARI) a(n)=if(n<0, 0, t=1; while(denominator(sigma(t)/numdiv(t))!=n, t++); t)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jul 26 2021
EXTENSIONS
a(29)-a(36) from Amiram Eldar, Jul 26 2021
a(37) from David A. Corneth, Jul 26 2021
a(38)-a(39) from Jinyuan Wang, Jul 26 2021
STATUS
approved