Natural numbers n for which the following three properties hold: (i) Phi[Sigma[n]]=2*phi(n), (ii) Sigma[n-2]=2*Sigma[Phi[n-2]], (iii) Sigma[n+2]=2*Sigma[Phi[n+2]].

A057564

Natural numbers n for which the following three properties hold: (i) Phi[Sigma[n]]=2*phi(n), (ii) Sigma[n-2]=2*Sigma[Phi[n-2]], (iii) Sigma[n+2]=2*Sigma[Phi[n+2]].

Terms

    a(0) =666a(1) =19674a(2) =309114a(3) =369594a(4) =715194a(5) =1180026a(6) =1924794a(7) =2722266a(8) =2741274a(9) =4261914a(10) =5564826a(11) =6296634a(12) =6623226a(13) =6826266a(14) =7206906a(15) =9726648a(16) =15956154a(17) =16046874a(18) =16478874a(19) =19263546a(20) =25333146a(21) =27706554a(22) =28151514a(23) =32938074

External references