109117domain: NAppears in sequencesZsigmondy numbers for a = 7, b = 3: Zs(n, 7, 3) is the greatest divisor of 7^n - 3^n that is relatively prime to 7^m - 3^m for all positive integers m < n.at n=17A109348Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2.at n=24A180826