|
|
A255885
|
|
Smallest base b such that there exist exactly n Wieferich pseudoprimes (composites c satisfying b^(c-1) == 1 (mod c^2)) less than b.
|
|
5
|
|
|
17, 65, 145, 485, 649, 1297, 577, 2024, 5185, 8182, 7057, 8749, 14401, 30753, 56449, 57601, 77401, 129473, 51841, 129601, 254017, 296449, 202501, 389377
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
PROG
|
(PARI) for(n=1, 10, b=2; while(b > 0, i=0; forcomposite(c=2, b, if(Mod(b, c^2)^(c-1)==1, i++)); if(i==n, print1(b, ", "); break({1})); b++))
(Python)
from itertools import count
from sympy import isprime
for b in count(1):
if n == sum(1 for c in range(2, b+1) if not isprime(c) and pow(b, c-1, c**2) == 1):
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|