27644

Appears in sequences

• Numbers k such that phi(k) + phi(k+1) = k.at n=18A067796
• Numbers whose Schwarzian arithmetic derivative is an integer.at n=33A209872
• Solutions of the equation k'' = tau(k) * k', where k' and k'' are the first and the second arithmetic derivative of k.at n=11A230544
• Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)).at n=38A327045
• a(n) = number of pairs {x,y} with (x,y > 1) such that x^y (= terms of A072103) has bit length n.at n=32A365930