7056721

Appears in sequences

• Pseudoprime Chebyshev numbers: odd composite integers n such that T_n(a) == a (mod n) for all integers a, where T(x) is Chebyshev polynomial of first kind.at n=0A175530
• Squarefree composite numbers n such that p^2 - 1 divides n^2 - 1 for every prime p dividing n.at n=7A287119
• Composite squarefree numbers k such that k^2-1 is divisible by p-1 and p+1, where p are all the prime factors of k.at n=22A306685