3334800

Appears in sequences

• Numbers k such that phi(sigma(k))/sigma(phi(k)) = 2.at n=19A229238
• a(n) = [x^n] Product_{k=0..n} (1 + k*x)^4.at n=5A384031
• E.g.f. A(x) satisfies A(x) = 1 + x*exp(x^2)*A(x)^2.at n=7A387714