OFFSET
0,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 0..1000
FORMULA
a(n) <= A065588(n). - Michael S. Branicky, Feb 05 2021
PROG
(Python)
from sympy import isprime
def a(n):
if n < 2: return list([2, 5])[n]
n5s, i, pow10 = int('5'*n), 1, 1
while True:
i = 1
while i < pow10:
t = n5s * pow10 + i
if isprime(t): return t
i += 2
pow10 *= 10
print([a(n) for n in range(20)]) # Michael S. Branicky, Feb 05 2021
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Feb 20 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Feb 21 2002
Corrected by Don Reble, Jan 17 2007
STATUS
approved