201173

Appears in sequences

• Numbers n such that sigma(phi(n))/sigma(n) = 3.at n=26A067383
• a(1)=1; a(n+1) = Sum_{k=1..n} a(k) a(floor(n/k)).at n=14A097417
• Expansion of g^3/(1 + x^2*g^4), where g = 1+x*g^3 is the g.f. of A001764.at n=8A391307