63973

Appears in sequences

• Carmichael numbers: composite numbers k such that a^(k-1) == 1 (mod k) for every a coprime to k.at n=14A002997
• Gaps of 9 in sequence A038593 (upper terms).at n=31A038658
• Base-3 Euler-Jacobi pseudoprimes.at n=30A048950
• Pseudoprimes to both base 2 and base 3, i.e., intersection of A001567 and A005935.at n=16A052155
• Numbers k such that phi(k)/lambda(k) increases to a record value, where phi(k) is the Euler totient function (A000010) and lambda(k) is the Carmichael lambda function (A002322).at n=24A066605
• Carmichael numbers with exactly 4 prime factors.at n=2A074379
• Numbers k such that phi(k) is a perfect sixth power.at n=37A078166
• Sarrus numbers with more than 2 distinct prime factors.at n=34A080747
• Pseudoprimes to bases 2 and 5.at n=13A083732
• Pseudoprimes to bases 3 and 5.at n=11A083734
• Pseudoprimes to bases 2, 3 and 5.at n=9A083737
• Carmichael numbers C such that C-1 is not a Niven/Harshad number.at n=1A097061
• Carmichael numbers that are not == 1 mod 24.at n=6A097130
• 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=16A104016
• Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.at n=7A112441
• Multiples of 1729, the Hardy-Ramanujan number.at n=37A138129
• Carmichael numbers with more than 3 prime factors.at n=2A141711
• Binomial transform of A010054 (characteristic function of triangular numbers).at n=18A143961
• a(n) = A027762(n)/A165734(n).at n=17A165949
• a(n) = (n-5)*(n-6)*(n-7)*(n-16)/24.at n=36A167543