OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..789 (terms below 10^10)
MATHEMATICA
f[e_] := If[OddQ[e], e + 2, e + 1]; fun[p_, e_] := 1 + (p^f[e] - p)/(p^2 - 1); a[1] = 1; a[n_] := Times @@ (fun @@@ (fct = FactorInteger[n])) - If[AllTrue[fct[[;; , 2]], OddQ], n, 0]; s = {}; Do[m = a[n]; If[m > n && a[m] == n, AppendTo[s, n]], {n, 1, 10^5}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Sep 07 2019
STATUS
approved