Fixed points of 1+Phi power sigma function 1PhiPsigma: if j = Product p_i^r_i then 1PhiPsigma(j) = Product {Sum p_i^r_i, 0 <= s_i < r_i, s_i is 0 or coprime to r_i} 1PhiPsigma(j) = j.
Factorizations: 2^2*3, 2^3*7, 2^4*3*11, 2^5*31, 2^6*3*5*7, 2^7*127, 2^10*3*7*31. If m is a perfect number then 2*m is a term of the sequence. Examples: 2^2*3, 2^3*7, 2^5*31, 2^7*127, .... If a(n)=2^r*k, GCD(2^r,k)=1, then k is squarefree.