cp's OEIS Frontend

A324381 Number of nonzero digits when the n-th highly composite number is written in primorial base: a(n) = A267263(A002182(n)).

%I A324381 #8 Feb 26 2019 19:12:29
%S A324381 1,1,1,1,1,1,2,2,1,1,1,2,2,2,1,1,1,2,2,2,2,2,2,2,1,3,3,2,2,2,2,2,2,2,
%T A324381 2,3,3,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,2,3,2,2,2,2,2,2,3,3,3,3,2,3,3,2,
%U A324381 2,3,2,2,2,2,2,3,3,3,3,3,3,3,2,3,2,3,2,3,2,3,4,3,3,3,3,3,2,3,3,3,2,3,3,3,4
%N A324381 Number of nonzero digits when the n-th highly composite number is written in primorial base: a(n) = A267263(A002182(n)).
%H A324381 Antti Karttunen, <a href="/A324381/b324381.txt">Table of n, a(n) for n = 1..10000</a>
%H A324381 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%H A324381 <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a>
%F A324381 a(n) = A267263(A002182(n)).
%F A324381 a(n) <= A324382(n).
%e A324381 For n=12, A002182(12) = 240, which is written as "11000" in primorial base (A049345) because 240 = 1*A002110(4) + 1*A002110(3) = 210+30, thus a(12) = 2, as there are two nonzero digits.
%e A324381 For n=18, A002182(18) = 2520 = "110000" in primorial base because 2520 = 1*A002110(5) + 1*A002110(4) = 2310+210, thus a(18) = 2.
%e A324381 For n=26, A002182(26) = 45360 = "1670000" in primorial base because 45360 = 1*A002110(6) + 6*A002110(5) + 7*A002110(4), thus a(26) = 3, as there are three nonzero digits.
%o A324381 (PARI)
%o A324381 A267263(n) = { my(s=0); forprime(p=2, , if(n%p, s++, if(n==0, return(s))); n\=p); }; \\ From A267263
%o A324381 A324381(n) = A267263(A002182(n));
%Y A324381 Cf. A002100, A002182, A049345, A267263, A324382.
%Y A324381 Cf. also A324341.
%K A324381 nonn
%O A324381 1,7
%A A324381 _Antti Karttunen_, Feb 26 2019