58438

Appears in sequences

• Numbers n such that sigma(2*phi(n)) = 2*sigma(n).at n=26A137733
• G.f.: ((1+2*x)*sqrt(1-6*x^2+x^4)-1+5*x^2-2*x^3)/(2*x*(1-6*x^2)).at n=15A212205
• a(n) = A212205(2*n + 1).at n=7A225887