OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
a[1] = 1; a[n_] := Module[{k = 1, d}, While[DivisorSigma[0, k] < n || ! PrimeQ[d = Divisors[k][[n]]], k++]; d]; Array[a, 30] (* Amiram Eldar, Feb 06 2019 *)
PROG
(Maxima) A119317(n) := block(
if equal(n, 1) then
return(1),
for i : 1 do (
idv : listify(divisors(i)),
if length(idv) >= n then (
if primep(idv[n]) then
return(idv[n])
)
)
)$ /* R. J. Mathar, Mar 13 2012 */
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 15 2006
EXTENSIONS
More terms from Amiram Eldar, Feb 06 2019
STATUS
approved