3581761

Appears in sequences

• Absolute Euler pseudoprimes: odd composite numbers n such that a^((n-1)/2) == +-1 (mod n) for every a coprime to n.at n=26A033181
• Carmichael numbers which are also base-2 strong pseudoprimes.at n=6A063847
• Strong pseudoprimes (base-2) equal to product of 3 primes not necessarily distinct.at n=14A112450
• a(n) is the smallest Carmichael number (A002997) with the n-th prime as its smallest prime divisor, or 0 if no such number exists.at n=8A135720
• a(n) is the least Carmichael number of the form prime(n)*prime(n')*prime(n") with n < n' < n", or 0 if no such number exists.at n=9A141705
• Fermat pseudoprimes to base 2 of the form (p^2 + 2*p)/3, where p is also a Fermat pseudoprime to base 2.at n=3A216276
• Carmichael numbers k such that the odd part of k-1 is squarefree.at n=9A263403
• Carmichael numbers (A002997) that are the sum of two squares.at n=19A265237
• The least 3-Carmichael number that is divisible by the n-th odd prime, or 0 if no such number exists.at n=28A290486
• Numbers k having at least one prime factor p such that p^2 divides 2^(k-1) - 1.at n=10A291194
• Numbers k such that gcd(k^2, 2^(k-1) - 1) > k.at n=8A331021
• Squarefree base-2 Fermat pseudoprimes divisible by a Wieferich prime.at n=0A353221
• Carmichael numbers whose number of prime factors is prime.at n=34A355039
• Carmichael numbers k such that k-1 is a Novak-Carmichael number.at n=12A375322
• Composites that cause a witness to be added to a set of Fermat witnesses: a(n) is the smallest composite number that is not guaranteed composite using Fermat's Little Theorem by the witness A380978(i) for any i < n.at n=14A380979