OFFSET
1,1
COMMENTS
Also composite n such that binomial(7*n,7)== n (mod n^2). - Gary Detlefs, Sep 24 2013
PROG
(PARI) isok(n) = ! isprime(n) && ((binomial(n+6, n) % n) == 1); \\ Michel Marcus, Sep 25 2013
(PARI) isok(n) = ! isprime(n) && ((binomial(7*n, 7) % n^2) == n); \\ Michel Marcus, Sep 25 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Hieronymus Fischer, Sep 30 2007
STATUS
approved