22926

Appears in sequences

• Composite and even n such that phi(n) * sigma(n) is one less than a square.at n=24A015721
• a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 2.at n=34A050031
• a(n) is the least integer k such that k/Fibonacci(n) > 4/5.at n=23A293672
• a(n) is the integer k that minimizes |k/Fibonacci(n) - 4/5|.at n=23A293673
• Composite numbers k such that phi(k) * psi(k) + 1 is a perfect square, where phi is the Euler totient function (A000010) and psi is the Dedekind psi function (A001615).at n=35A309653