OFFSET
1,3
REFERENCES
A. Murthy, Some new Smarandache sequences, functions and partitions, Smarandache Notions Journal Vol. 11 N. 1-2-3 Spring 2000
PROG
(PARI) is(n) = isprime(90*n+11) && isprime(90*n+13) && isprime(90*n+17) && isprime(90*n+19); \\ Michel Marcus, Sep 28 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Felice Russo, Dec 17 1999
STATUS
approved