n=15 mode=0 seed=7  S_n mod p = 0
n=16 mode=0 seed=7  S_n mod p = 0
n=17 mode=0 seed=7  S_n mod p = 0
n=18 mode=0 seed=7  S_n mod p = 0
n=19 mode=0 seed=7  S_n mod p = 0
n=20 mode=0 seed=7  S_n mod p = 0
n=21 mode=0 seed=7  S_n mod p = 0
n=17 mode=1 seed=3  S_n mod p = 1657232068526083916
n=18 mode=1 seed=3  S_n mod p = 2208789304440695594
