|
%I #23 Jul 03 2022 06:47:14
%S 144,324,400,784,1936,2025,2500,2704,3969,4624,5625,5776,8464,9604,
%T 9801,13456,13689,15376,16384,21609,21904,23409,26896,29241,29584,
%U 30625,35344,42849,44944,55696,58564,59536,60025,68121,71824,75625
%N Numbers with 15 divisors.
%C Numbers of the form p^14 (subset of A010802) or p^2*q^4 (A189988) where p and q are distinct primes. - _R. J. Mathar_, Mar 01 2010
%H R. J. Mathar, <a href="/A030633/b030633.txt">Table of n, a(n) for n = 1..1000</a>
%F From _Amiram Eldar_, Jul 03 2022: (Start)
%F A000005(a(n)) = 15.
%F Sum_{n>=1} 1/a(n) = P(2)*P(4) - P(6) + P(14) = 0.0178111..., where P is the prime zeta function. (End)
%t Select[Range[300000],DivisorSigma[0,#]==15&] (* _Vladimir Joseph Stephan Orlovsky_, May 05 2011 *)
%o (PARI) is(n)=numdiv(n)==15 \\ _Charles R Greathouse IV_, Jun 19 2016
%Y Cf. A000005, A010802, A030630, A030631, A030632, A189988.
%K nonn
%O 1,1
%A _Jeff Burch_
|
