5049001

Appears in sequences

• Carmichael numbers which are also base-2 strong pseudoprimes.at n=8A063847
• Strong pseudoprimes (base-2) equal to product of 3 primes not necessarily distinct.at n=17A112450
• Carmichael numbers divisible by 31.at n=13A182151
• Carmichael numbers that have only prime divisors of the form 10k+1.at n=9A212843
• Strong pseudoprimes (base 2) that become prime when two is subtracted.at n=19A230483
• Strong pseudoprimes k to base 2 such that either k-2 or k+2 is prime.at n=26A230487
• Carmichael numbers k such that phi(k) divides (k-1)*lambda(k).at n=18A306338
• Numbers that are both Fermat pseudoprimes to base 2 (A001567) and Bruckman-Lucas pseudoprimes (A005845).at n=25A329240
• Euler-Fibonacci pseudoprimes: odd composites k such that F(k) == 5^((k-1)/2) == +-1 (mod k), where F(k) = A000045(k), the Fibonacci numbers.at n=19A345753
• Base-2 Fermat pseudoprimes k such that the multiplicative order of 2 modulo k is odd.at n=30A367230
• Carmichael numbers k such that the multiplicative order of 2 modulo k is odd.at n=2A367231
• Composite numbers k such that 2^(2^(k-1)-1) == 1 (mod k^2).at n=13A376253
• Carmichael numbers that are the sum of 2 positive cubes.at n=9A379656