104978domain: NAppears in sequencesNumbers of the form k^2 + 2 that are the sums of two squares.at n=28A329170a(n) = Sum_{1 <= x_1 <= x_2 <= x_3 <= x_4 <= x_5 <= x_6 <= n} gcd(x_1, x_2, x_3 , x_4, x_5, x_6, n).at n=17A343520Numbers k such that there exists i >= 1 such that k divides 3^3^i - 1.at n=30A367265