OFFSET
1,1
COMMENTS
Numbers of the forms p^38 and p^12*q^2, where p and q are distinct primes.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
OEIS Wiki, Index entries for number of divisors
FORMULA
A000005(a(n)) = 39.
Sum_{n>=1} 1/a(n) = P(2)*P(12) - P(14) + P(38) = 0.0000500204..., where P is the prime zeta function. - Amiram Eldar, Jul 03 2022
MATHEMATICA
Select[Range[7000000], DivisorSigma[0, #]==39&] (* Vladimir Joseph Stephan Orlovsky, May 06 2011 *)
PROG
(PARI) is(n)=numdiv(n)==39 \\ Charles R Greathouse IV, Jun 19 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 27 2010
EXTENSIONS
Extended by T. D. Noe, May 08 2011
STATUS
approved