OFFSET
1,1
COMMENTS
These are numbers of the form p^e*((p-1)*p^(e-1) + 1) where p is an odd prime and (p-1)*p^(e-1) + 1 is prime.
{A002322(a(n))} = {6, 18, 42, 100, 156, 162, ...} is a permutation of A114874 without the terms that are powers of 2 (but they don't have the same order: 6563187324027001 and 6575415997816513 are both terms but A002322(6563187324027001) = 81009000 while A002322(6575415997816513) = 80995248).
A305236 = {a(n)} U {2*a(n)} U {8, 12}.
LINKS
Jianing Song, Table of n, a(n) for n = 1..156 (all terms below 10^16)
EXAMPLE
See A305236 for examples.
PROG
(PARI) the_first_entries(nn) = my(u=[]); for(n=2, sqrt(nn), my(v=factor(n), d=#v[, 1], p=v[d, 1], e=v[d, 2]); if(isprime(n+1) && p!=2 && n==(p-1)*p^e, u=concat(u, [(n+1)*p^(e+1)]))); u=vecsort(select(i->(i<nn), u)); u
CROSSREFS
KEYWORD
nonn
AUTHOR
Jianing Song, Apr 12 2019
STATUS
approved