OFFSET
1,2
COMMENTS
a(n) is the median of the values ofA000203(m) from m=1 to m=2n-1. (This needs confirmation as it relies on the assumption thatA000203(n) is always bigger than the median of the valuesA000203(x) from x=1 to x=n.) -Chayim Lowen,May 27 2015
LINKS
T. D. Noe,Table of n, a(n) for n = 1..10000
FORMULA
a(n) = sigma(A085790(n)). -Jinyuan Wang,Apr 15 2020
MAPLE
sort(select(`<=`, map(numtheory:-sigma, [$1..1000]), 1001)); #Robert Israel,Jun 04 2015
MATHEMATICA
terms = 68; ClearAll[t]; t[k_]:= t[k] = Sort[ Table[ DivisorSigma[1, n], {n, 1, k*terms}]][[1;; terms]]; t[k = 2]; While[t[k]!= t[k-1], k++]; t[k] (*Jean-François Alcover,Nov 21 2012 *)
With[{nn=80}, Take[Sort[DivisorSigma[1, Range[nn*100]]], nn]] (*Harvey P. Dale,Mar 09 2016 *)
PROG
(PARI) list(lim)=select(k->k<=lim, Set(apply(sigma, [1..lim\1]))) \\Charles R Greathouse IV,Mar 09 2014
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
STATUS
approved