OFFSET
1,1
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000 (first 500 terms from Pierre CAMI)
EXAMPLE
3*4=12: 11 and 13 are twin primes; 3*6=18 and 17 and 19 are also twin primes.
PROG
(PARI) isok(n) = isprime(n*(n+1)-1) && isprime(n*(n+1)+1) && isprime(n*(n+3)-1) && isprime(n*(n+3)+1); \\ Michel Marcus, Sep 23 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Mar 13 2008
STATUS
approved