625974domain: NAppears in sequencesa(n) = 729*n^2 - 1016*n + 354.at n=29A157665Starts of runs of 3 consecutive numbers whose powerful part is larger than their powerfree part (A328014).at n=13A348120Numbers k such that k^(k + 1) == k + 1 (mod 2*k + 1) while 2*k+1 is not prime.at n=22A380831