OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..528 (terms below 2*10^11, from David Moews's site).
David Moews, Perfect, amicable and sociable numbers.
EXAMPLE
2024 is in the sequence since it is the lesser of the amicable pair (2024, 2295): bsigma(2024) = bsigma(2295) = 4320 = 2024 + 2295 + 1.
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
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 14 2019
STATUS
approved