OFFSET
1,1
COMMENTS
a(n) >= A039678(n) for all n.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..100
MATHEMATICA
Array[Block[{b = 2}, While[PowerMod[b, # - 1, #^3] != 1, b++]; b] &@ Prime@ # &, 45] (* Michael De Vlieger, Nov 25 2018 *)
dpa[n_]:=Module[{p=Prime[n], a=9}, While[PowerMod[a, p - 1, p^3]!=1, a++]; a]; Array[dpa, 50] (* Vincenzo Librandi, Nov 30 2018 *)
PROG
(PARI) a(n) = my(p=prime(n)); for(b=2, oo, if(Mod(b, p^3)^(p-1)==1, return(b)))
(Python)
from sympy import prime
def a(n):
b, p = 2, prime(n)
p3 = p**3
while pow(b, p-1, p3) != 1: b += 1
return b
print([a(n) for n in range(1, 46)]) # Michael S. Branicky, Sep 26 2021
(Python)
from sympy import prime
from sympy.ntheory.residue_ntheory import nthroot_mod
def A249275(n): return 2**3+1 if n == 1 else int(nthroot_mod(1, (p:= prime(n))-1, p**3, True)[1]) # Chai Wah Wu, May 17 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Oct 24 2014
EXTENSIONS
Edited by Felix Fröhlich, Nov 24 2018
STATUS
approved