OFFSET
1,1
PROG
(PARI) isok(n) = {my(p=2*prime(n)+1, q=2*prime(n+1)+1, r=2*prime(n+2)-3, s=2*prime(n+3)+3); isprime(p) && (nextprime(p+1) == q) && (nextprime(q+1) == r) && (nextprime(r+1) == s); } \\ Michel Marcus, Sep 24 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Feb 21 2005
STATUS
approved