1615681
domain: N
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=17A033181
- Pseudoprimes to bases 2,5 and 7.at n=29A083736
- Pseudoprimes to bases 2, 3, 5 and 7.at n=24A083739
- Pseudoprimes to bases 3,5 and 7.at n=28A083740
- Product of Lucas (A000204) and a Pell companion series (A001333).at n=10A085292
- 3-Carmichael numbers: Carmichael numbers equal to the product of 3 primes: k = p*q*r, where p < q < r are primes such that a^(k-1) == 1 (mod k) if a is prime to k.at n=27A087788
- Records in A098650.at n=23A098652
- 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=7A135720
- 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=8A141705
- a(n) is the largest Carmichael number of the form prime(n)*prime(n')*prime(n") with n < n' < n", or 0 if no such number exists.at n=8A141706
- Carmichael numbers (A002997) that are the sum of three consecutive primes.at n=2A270267
- Fermat pseudoprimes (A001567) that are the sum of three consecutive primes.at n=15A270639
- The largest 3-Carmichael number that is divisible by the n-th odd prime.at n=7A290485
- Numbers n with record number of primes p such that n*p is a Carmichael number.at n=6A292366
- Carmichael numbers c with record number of primes p such that c*p is also a Carmichael number.at n=3A292367
- a(n) is the smallest Carmichael number k such that gpf(p-1) = prime(n) for all prime factors p of k.at n=3A327787
- Carmichael numbers ending in 1.at n=30A354609
- Carmichael numbers whose number of prime factors is prime.at n=29A355039
- Carmichael numbers k such that k-1 is a Novak-Carmichael number.at n=8A375322
- 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=12A380979