53391domain: NAppears in sequencesa(n) = A083960(n)/A004151(n).at n=20A083961a(n) = A083960(n)/A004151(n).at n=41A083961a(n) = (n-1)^2*(n+1).at n=38A152618Numbers k such that k = x + y, k' = x' + y' and k'' = x'' + y'', where k' and k'' are the first and second arithmetic derivatives of k.at n=15A293252