OFFSET
1,1
PROG
(Python)
from sympy import isprime
from itertools import count, islice
def agen(): # generator of terms
s = ""
while True:
for d in "13":
for k in count(1):
if isprime(int(s+d*k)): break
yield k
s += d*k
print(list(islice(agen(), 10))) # Michael S. Branicky, Aug 23 2022
CROSSREFS
KEYWORD
base,nonn,more
AUTHOR
Amarnath Murthy, Aug 12 2005
EXTENSIONS
Corrected and extended by Joshua Zucker, Jan 11 2006
a(11) from Michael S. Branicky, Aug 23 2022
a(12)-a(13) from Michael S. Branicky, May 29 2023
STATUS
approved