OFFSET
1,1
COMMENTS
First differs from A306588 at n=15.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..314
EXAMPLE
3 is a term since A004394(3)-1 = 4-1 = 3 is prime.
MATHEMATICA
s = {}; abm = 0; k = 0; Do[ab = DivisorSigma[-1, n]; If[ab > abm, abm = ab; k++; If[PrimeQ[n - 1], AppendTo[s, k]]], {n, 1, 10^6}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 10 2022
STATUS
approved