OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
It seems that Sum_{k=1..n} a(k) is asymptotic to C*n*log(n)*log(log(n)) with C>1.
MATHEMATICA
a[n_] := Module[{k = 1, r = DivisorSigma[-1, n]}, While[DivisorSigma[-1, k] < r, k++]; k]; Array[a, 100] (* Amiram Eldar, May 05 2022 *)
PROG
(PARI) a(n)=if(n<0, 0, s=1; while(sigma(s)/s<sigma(n)/n, s++); s)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 23 2002
STATUS
approved