A225945 Numbers k such that prime(k) divides k^k + 1.

1, 6, 60, 136, 124796, 3919272, 18363918, 153037808, 965108649, 3140421892, 5961162423, 20437804784

Offset: 1

Author

Alex Ratushnyak, May 21 2013

Keywords

• nonn
• more

Comments

a(12) > 2*10^10. - Giovanni Resta, May 23 2013

Crossrefs

Cf. A000040, A000312, A014566, A225944.

Programs

Mathematica

Select[Range[10^6], (p = Prime[#]; PowerMod[#, #, p] == p - 1) &] (* Giovanni Resta, May 23 2013 *)

Python

from sympy import nextprime, prime
from itertools import count, islice
def agen(startn=1): # generator of terms
    pn = prime(startn)
    for n in count(startn):
        if pow(n, n, pn) == pn - 1:
            yield n
        pn = nextprime(pn)
print(list(islice(agen(), 5))) # Michael S. Branicky, May 25 2023

Extensions

a(6)-a(11) from Giovanni Resta, May 23 2013

a(12) from Michael S. Branicky, May 25 2023