OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..64
EXAMPLE
7^2-1 = 48 has 10 factors, which is the largest for any prime <= 7 (5^2-1 has 8 factors, 3^2-1 has 4 factors, and 2^2-1 has 2 factors).
MATHEMATICA
seq[len_] := Module[{s = {}, p = 2, dm = 0, c = 0, d}, While[c < len, If[(d = DivisorSigma[0, p^2 - 1]) > dm, dm = d; c++; AppendTo[s, p]]; p = NextPrime[p]]; s]; seq[30] (* Amiram Eldar, Jul 07 2022 *)
PROG
(PARI) my(r=0, d); forprime(p=2, 3*10^6, if((d=numdiv(p^2-1))>r, r=d; print1(p, ", "))); \\ Joerg Arndt, Jun 01 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Austin Nguyen Tran, May 31 2020
STATUS
approved