666666666668domain: NAppears in sequencesNumbers k such that k^2 contains only digits {2,4,6}.at n=20A053922Number of Fibonacci numbers F(k), k <= 10^n, which end in 8.at n=12A073555Numbers k such that k and k^2 use only the digits 2, 4, 6 and 8.at n=14A137103Numbers k such that k + phi(k) is a power of 10.at n=14A244440