2545920

Appears in sequences

• Smallest k such that d(phi(k)) - phi(d(k)) = -n, where d(k) = A000005(k) and phi(k) = A000010(k).at n=20A078151
• a(n) = sigma(3*a(n-1)) for n>1 with a(1)=1.at n=7A180708