67973

Appears in sequences

• Numbers k such that 155*2^k+1 is prime.at n=23A032454
• Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 15.at n=34A051980
• Numbers k such that k = p+q = r+s with p*q = r*s = primorial number(A002110) (p*q) < (r*s).at n=5A057230
• Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 606", based on the 5-celled von Neumann neighborhood.at n=8A273205