181876

Appears in sequences

• Smallest number k > 0 such that sigma(x) and sigma(x)+2 are both prime, where x = (6k+1)^(6n+4), or -1 if no such k exists.at n=13A275237
• Numbers k such that 6k+1, 6k+5, 6k+7, 6k+11, 6k+13 and 6k+17 are prime.at n=5A374414