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%I #8 Apr 03 2024 17:02:40
%S 1,4,8,9,12,16,18,20,24,25,27,28,30,32,40,42,44,45,48,49,50,52,54,56,
%T 63,64,66,68,70,75,76,78,80,81,88,92,96,98,99,102,104,105,110,112,114,
%U 116,117,121,124,125,128,130,135,136,138,147,148,152,153,154,160,162,164,165
%N Numbers with equal numbers of prime and semiprime divisors.
%H Harvey P. Dale, <a href="/A345212/b345212.txt">Table of n, a(n) for n = 1..1000</a>
%e 1 has 0 prime divisors and 0 semiprime divisors.
%e 30 is in the sequence since it has 3 prime divisors: {2,3,5} and 3 semiprime divisors {6,10,15}.
%t pdsdQ[n_]:=Module[{divs=Divisors[n]},Count[divs,_?(PrimeQ[#]&)]==Count[divs,_?(PrimeOmega[ #]==2&)]]; Select[Range[200],pdsdQ] (* _Harvey P. Dale_, Apr 03 2024 *)
%Y Cf. A000040 (primes), A001358 (semiprimes).
%K nonn
%O 1,2
%A _Wesley Ivan Hurt_, Jun 10 2021
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