cp's OEIS Frontend

A355275 Numbers having more odd than even digits when written in base 3.

%I A355275 #12 Mar 04 2024 01:31:18
%S A355275 1,4,10,12,13,14,16,22,31,37,39,40,41,43,49,67,85,91,93,94,95,97,103,
%T A355275 109,111,112,113,115,117,118,119,120,121,122,123,124,125,127,129,130,
%U A355275 131,133,139,145,147,148,149,151,157,175,193,199,201,202,203,205,211,229,256,274,280,282,283,284,286,292
%N A355275 Numbers having more odd than even digits when written in base 3.
%C A355275 If k is a term, then so is 3*k+1. - _Robert Israel_, Mar 04 2024
%H A355275 Robert Israel, <a href="/A355275/b355275.txt">Table of n, a(n) for n = 1..10000</a>
%p A355275 filter:= proc(n) local L;
%p A355275   L:= convert(n,base,3);
%p A355275   numboccur(1,L) > nops(L)/2
%p A355275 end proc:
%p A355275 select(filter, [$1..1000]); # _Robert Israel_, Mar 04 2024
%o A355275 (PARI) select( {is_A355275(n)=vecsum(n=digits(n,3)%2)*2>#n}, [0..299])
%o A355275 (Python)
%o A355275 from sympy.ntheory import digits
%o A355275 def ok(n):
%o A355275     d = digits(n, 3)[1:]
%o A355275     return len(d) < 2*sum(1 for di in d if di%2)
%o A355275 print([k for k in range(293) if ok(k)]) # _Michael S. Branicky_, Jul 03 2022
%Y A355275 Cf. A072600 (same in base 2), A352547 (same in base 10).
%K A355275 nonn,base
%O A355275 1,2
%A A355275 _M. F. Hasler_, Jul 03 2022