2100901
domain: N
Appears in sequences
- Carmichael numbers with exactly 4 prime factors.at n=23A074379
- Pseudoprimes to bases 2, 3, 5 and 7.at n=27A083739
- Carmichael numbers that are not == 1 mod 24.at n=18A097130
- Carmichael numbers with more than 3 prime factors.at n=25A141711
- Carmichael numbers divisible by 11.at n=7A182090
- Carmichael numbers divisible by 31.at n=9A182151
- Carmichael numbers of the form C = p*(2p-1)*(n*(2p-2)+p), where p and 2p-1 are prime numbers.at n=21A182207
- Carmichael numbers that have only prime divisors of the form 10k+1.at n=7A212843
- Composite numbers k such that k divides Fibonacci(k+1) or Fibonacci(k-1) and 2^(k-1) == 1 (mod k).at n=25A214434
- Composite numbers n such that gcd(phi(n), n-1) = lambda(n), where lambda(n) = A002322(n).at n=23A264012
- Numbers that are both Fermat pseudoprimes to base 2 (A001567) and Bruckman-Lucas pseudoprimes (A005845).at n=16A329240
- 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=11A345753
- Carmichael numbers ending in 1.at n=33A354609
- The lesser of twin Carmichael numbers: a pair of consecutive Carmichael numbers (A002997) without a non-prime-power weak Carmichael number (A087442) between them.at n=7A365022
- Smallest n-bit Carmichael number, or 0 if no such number exists.at n=12A375875