This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A095724 #24 Dec 05 2024 09:26:36
%S A095724 12,56,528,992,6720,16256,666624,67100672
%N A095724 Fixed points of 1+Phi power sigma function 1PhiPsigma: integers m such that 1PhiPsigma(m) = m, where for j = Product p_i^r_i, 1PhiPsigma(j) = Product_i Sum_{0 <= s_i <= r_i, s_i is 0 or coprime to r_i} p_i^s_i.
%C A095724 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.
%C A095724 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, ....
%C A095724 If a(n)=2^r*k, GCD(2^r,k)=1, then k is squarefree.
%e A095724 1PhiPsigma(2^5*3^4) = (1 + 2 + 2^2 + 2^3 + 2^4)*(1 + 3 + 3^3) = 961.
%Y A095724 Cf. A061389, A095723.
%K A095724 nonn,more
%O A095724 1,1
%A A095724 _Yasutoshi Kohmoto_, Jul 08 2004
%E A095724 a(8) from _Jud McCranie_, Jul 16 2004
%E A095724 Edited by _Max Alekseyev_, Dec 04 2024