OFFSET
1,2
COMMENTS
It is only a conjecture that a(n) always exists. - Editors, OEIS, Mar 07 2017
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
PROG
(Python)
from sympy import isprime
a = [1]
found = True
while found:
found = False
prev = a[len(a)-1]
for k in range(2, 10001):
if isprime(prev*k-1) and isprime(prev*k+1) and (k not in a):
print str(k)+', ',
a.append(k)
found = True
break
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Feb 17 2017
STATUS
approved