334153

Appears in sequences

• Carmichael numbers: composite numbers k such that a^(k-1) == 1 (mod k) for every a coprime to k.at n=26A002997
• a(n) = (9n^4 - 18n^3 + 18n^2 - 9n + 2)/2.at n=16A079903
• Pseudoprimes to bases 2 and 5.at n=27A083732
• Pseudoprimes to bases 2 and 7.at n=20A083733
• Pseudoprimes to bases 3 and 5.at n=26A083734
• Pseudoprimes to bases 3 and 7.at n=25A083735
• Pseudoprimes to bases 2,5 and 7.at n=9A083736
• Pseudoprimes to bases 2, 3 and 5.at n=20A083737
• Pseudoprimes to bases 2,3 and 7.at n=15A083738
• Pseudoprimes to bases 2, 3, 5 and 7.at n=8A083739
• Pseudoprimes to bases 3,5 and 7.at n=10A083740
• 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=17A087788
• Numerator of (9*(n^4 - 2*n^3 + 2*n^2 - n) + 2)/(2*(2*n-1)).at n=16A096430
• Records in A098650.at n=11A098652
• 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=29A104016
• Triangular numbers whose digit reversal is a brilliant number (A078972).at n=15A115678
• Nonprime numbers k such that k divides 3^((k+1)/2) - 2^((k+1)/2) - 1.at n=27A130062
• 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=6A135720
• a(n) is the smallest Carmichael number (A002997) divisible by the n-th prime, or 0 if no such number exists.at n=12A135721
• 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=7A141705