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%I #26 Nov 08 2023 21:03:01
%S 1,2,2,3,4,4,4,5,6,6,7,8,9,9,9,10,11,11,12,13,14,15,15,16,17,18,18,19,
%T 20,21,22,22,23,24,25,26,27,28,29,30,30,30,31,31,32,33,34,35,36,37,38,
%U 39,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,53,54,54,55,56,57,58,59,60
%N Number of primes <= the n-th prime power.
%C Also, number of distinct primes among the first n prime powers (cf. A246655).
%H Paolo Xausa, <a href="/A362965/b362965.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A000720(A246655(n)).
%t A362965list[upto_]:=PrimePi[Select[Range[upto],PrimePowerQ]];A362965list[500] (* _Paolo Xausa_, Jun 29 2023 *)
%o (PARI) apply(primepi, [p| p <- [1..300], isprimepower(p)]) \\ _Michel Marcus_, Jun 04 2023
%Y Cf. A000961, A000720, A246655, A366833 (run lengths).
%K nonn
%O 1,2
%A _Max Alekseyev_, Jun 03 2023
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