135813domain: NAppears in sequencesNumbers k such that the product of Euler phi of the 2 consecutive integers {k,k+1} is a 4th power: if sqrt(sqrt(phi(k)*phi(k+1))) is an integer, then k is here.at n=18A082788a(n) = 8 + floor( (1 + Sum_{j=1..n-1} a(j)) / 2).at n=24A120137