512461

Appears in sequences

• Carmichael numbers: composite numbers k such that a^(k-1) == 1 (mod k) for every a coprime to k.at n=32A002997
• a(n) = n^4 - n^3 + n^2 - n + 1.at n=27A060884
• Numbers of the form (3^s+1)/(3^r+1) for s > 1, 1 <= r <= s-1.at n=12A079672
• Pseudoprimes to bases 2 and 7.at n=26A083733
• Pseudoprimes to bases 2,5 and 7.at n=14A083736
• Pseudoprimes to bases 2, 3 and 5.at n=25A083737
• Pseudoprimes to bases 2,3 and 7.at n=21A083738
• Pseudoprimes to bases 2, 3, 5 and 7.at n=13A083739
• Pseudoprimes to bases 3,5 and 7.at n=15A083740
• a(n) = sigma_6(n^2)/sigma_3(n^2).at n=8A084220
• 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=21A087788
• Carmichael numbers that are not == 1 mod 24.at n=11A097130
• Structured small rhombicosidodecahedral numbers.at n=30A100148
• a(n) = 3*a(n-1) - a(n-3) + 3*a(n-4), with initial values 0,0,0,1.at n=15A133405
• Carmichael numbers divisible by 31.at n=5A182151
• Carmichael numbers of the form C = p*(2p-1)*(n*(2p-2)+p), where p and 2p-1 are prime numbers.at n=11A182207
• Carmichael numbers that have only prime divisors of the form 10k+1.at n=2A212843
• Composite numbers k such that k divides Fibonacci(k+1) or Fibonacci(k-1) and 2^(k-1) == 1 (mod k).at n=8A214434
• Carmichael numbers (A002997) that are not absolute Euler pseudoprimes (A033181).at n=21A262043
• Composite numbers n such that gcd(phi(n), n-1) = lambda(n), where lambda(n) = A002322(n).at n=17A264012