OFFSET
1,1
COMMENTS
Branicky searched n<=10000 to 1000 digits.
a(87) = 45*10^11959-1 (11961 digits). - Sidney Cadot, Jan 06 2023
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..86
Michael S. Branicky, Table of n, a(n) for n = 1..10000 (with "None" if the solution is unknown, with each such value tested to at least 1000 digits).
EXAMPLE
25th term is 9799...999, i.e., digits of Prime[25]=97 are followed by 90 copies of digit 9.
PROG
(Python)
from sympy import isprime, prime
def a(n, wlimit=1000):
if n == 2: return 0
pn, w = str(prime(n)), 1
while not isprime(int(pn+"9"*w)):
w += 1
if w > wlimit: return -1
return int(pn+"9"*w)
print([a(n) for n in range(1, 26)]) # Michael S. Branicky, May 07 2022
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Jul 13 2000
EXTENSIONS
Revised to handle p=3 by Sean A. Irvine, Apr 05 2022
STATUS
approved