A186641 Primes that are not cyclic numbers (A001913).

2, 3, 5, 11, 13, 31, 37, 41, 43, 53, 67, 71, 73, 79, 83, 89, 101, 103, 107, 127, 137, 139, 151, 157, 163, 173, 191, 197, 199, 211, 227, 239, 241, 251, 271, 277, 281, 283, 293, 307, 311, 317, 331, 347, 349, 353, 359, 373, 397, 401, 409, 421, 431, 439, 443, 449, 457, 463, 467, 479

Offset: 1

Author

Jani Melik, Feb 24 2011

Keywords

• nonn

Comments

Sequence A006559 with 2 and 5 included.

Programs

Maple

f1 := proc(n) local st, period:
st := ithprime(n):
period := numtheory[order](10,st):
if (st-1 <> period) then
   RETURN(st):
fi: end:  seq(f1(n), n=1..150);

Python

from itertools import islice
from sympy import nextprime, n_order
def A186641_gen(startvalue=1): # generator of terms >= startvalue
    p = max(startvalue-1,1)
    while (p:=nextprime(p)):
        if p==2 or p==5 or n_order(10,p)A186641_list = list(islice(A186641_gen(),20)) # Chai Wah Wu, Mar 03 2025