OFFSET
1,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Vincenzo Librandi)
MATHEMATICA
Flatten[Table[Select[FromDigits/@Tuples[{6, 7}, n], PrimeQ], {n, 8}]] (* Vincenzo Librandi, Jul 27 2012 *)
PROG
(Python)
from sympy import isprime
from itertools import count, islice, product
def agen(): # generator of terms
yield 7
for d in count(2):
for first in product("67", repeat=d-1):
t = int("".join(first) + "7")
if isprime(t): yield t
print(list(islice(agen(), 31))) # Michael S. Branicky, Nov 15 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved