2811271

Appears in sequences

• Strong pseudoprimes (base 2) that become prime when two is subtracted.at n=15A230483
• Strong pseudoprimes k to base 2 such that either k-2 or k+2 is prime.at n=22A230487
• Composite numbers k == 3 (mod 4) such that (1 + i)^k == 1 - i (mod k), where i = sqrt(-1).at n=21A270697
• Numbers k > 1 such that 2^k == 2 (mod k) and gcd(k, 3^k - 3) = 1.at n=30A300762
• Base-2 Fermat pseudoprimes k such that the multiplicative order of 2 modulo k is odd.at n=21A367230