|
%I #15 Jun 06 2022 05:47:30
%S 2,9,84,126,135,196,264,294,375,468,567,594,625,1040,1100,1232,1368,
%T 1824,2028,2052,2420,2704,2720,3042,3400,4416,6050,6125,7203,7986,
%U 8019,8500,8512,8575,8664,8928,9200,9234,11560,13020,16065,16250,19305
%N Numbers k such that the sum over the prime divisors of k equals the number of divisors of k.
%C For distinct primes p,q, includes p^a*q^b if (a+1)*(b+1)=p+q. - _Robert Israel_, Jan 05 2018
%H Robert Israel, <a href="/A069234/b069234.txt">Table of n, a(n) for n = 1..1000</a>
%F k such that A000005(k) = A008472(k).
%p filter:= n -> numtheory:-tau(n)=convert(numtheory:-factorset(n),`+`):
%p select(filter, [$1..10^5]); # _Robert Israel_, Jan 05 2018
%t Select[Range[20000], Plus @@ ((f = FactorInteger[#])[[;;, 1]]) == Times @@ (f[[;;, 2]] + 1) &] (* _Amiram Eldar_, Jun 06 2022 *)
%Y Cf. A000005, A008472.
%K easy,nonn
%O 1,1
%A _Benoit Cloitre_, Apr 13 2002
|
