OFFSET
1,2
COMMENTS
Does this sequence have density 1/3? This sequence has infinitely many terms because every prime number is a term.
The numbers of terms not exceeding 10^k for k = 1, 2, ... are 8, 50, 396, 3566, 33943, 332042, 3297317, 32983277, ... Apparently this sequence has an asymptotic density of about 0.33. - Amiram Eldar, Nov 18 2021
MATHEMATICA
a[n_] := Module[{s = NestWhileList[n*DivisorSigma[0, #] &, 1, UnsameQ, All]}, Differences[Position[s, s[[-1]]]][[1, 1]]]; Select[Range[130], a[#] == 1 &] (* Amiram Eldar, Nov 18 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Tejo Vrush, Nov 18 2021
STATUS
approved