188461

Appears in sequences

• Carmichael numbers: composite numbers k such that a^(k-1) == 1 (mod k) for every a coprime to k.at n=21A002997
• Pseudoprimes to both base 2 and base 3, i.e., intersection of A001567 and A005935.at n=31A052155
• Carmichael numbers with exactly 4 prime factors.at n=7A074379
• Pseudoprimes to bases 2 and 5.at n=23A083732
• Pseudoprimes to bases 3 and 5.at n=21A083734
• Pseudoprimes to bases 2, 3 and 5.at n=16A083737
• Carmichael numbers that are not == 1 mod 24.at n=9A097130
• Devaraj numbers: squarefree r-prime-factor (r>1) integers N=p1*...*pr such that phi(N)=(p1-1)*...*(pr-1) divides gcd(p1-1,...,pr-1)^2*(N-1)^(r-2).at n=24A104016
• Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.at n=16A112441
• a(n) is the smallest Carmichael number (A002997) divisible by the n-th prime, or 0 if no such number exists.at n=27A135721
• Carmichael numbers with more than 3 prime factors.at n=7A141711
• Odd composite numbers m for which A000111(m) == (-1)^( (m-1)/2 ) (mod m).at n=31A180942
• Carmichael numbers of the form C = p*(2p-1)*(n*(2p-2)+p), where p and 2p-1 are prime numbers.at n=7A182207
• Carmichael numbers divisible by 7.at n=11A182208
• Carmichael numbers divisible by 1729.at n=3A212920
• Carmichael numbers divisible by a smaller Carmichael number.at n=3A214758
• Pseudoprimes divisible by a smaller pseudoprime.at n=15A215150
• Carmichael numbers (A002997) that are not absolute Euler pseudoprimes (A033181).at n=13A262043
• Composite numbers n such that gcd(phi(n), n-1) = lambda(n), where lambda(n) = A002322(n).at n=12A264012
• Carmichael numbers m such that A309132(m) < m.at n=4A309268