A306867 Lesser of augmented bi-unitary amicable pair.
434784, 1100176, 1252216, 1754536, 2166136, 2362360, 3064096, 6224890, 7626136, 7851256, 7950096, 9026235, 9581320, 12494856, 13324311, 14192080, 15218560, 15243424, 15422536, 19028296, 19466560, 19555360, 29180466, 36716680, 37542190, 40682824, 44044000, 44588896
Offset: 1
Keywords
Examples
434784 is in the sequence since it is the lesser of the amicable pair (434784, 871585): bsigma(434784) = bsigma(871585) = 1306368 = 434784 + 871585 - 1.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..509 (terms below 2*10^11, from David Moews's site).
- David Moews, Perfect, amicable and sociable numbers.
Programs
-
Mathematica
fun[p_, e_]:=If[OddQ[e], (p^(e+1)-1)/(p-1), (p^(e+1)-1)/(p-1)-p^(e/2)]; bsigma[1] = 1; bsigma[n_] := Times @@ (fun @@@ FactorInteger[n]); f[n_] := bsigma[n] - n + 1; s={}; Do[m = f[n]; If[m > n && f[m] == n, AppendTo[s, n]], {n, 1, 10^7}]; s
Comments