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%I #13 Apr 24 2021 02:07:00
%S 777,2073,3369,4017,4233,4449,4557,4593,4629,4647,4653,4659,4662,4663,
%T 4664,4666,4667,4671,4677,4701,4737,4881,5097,5961,7257,8553,9849,
%U 11145,11793,12009,12225,12333,12369,12405,12423,12429
%N Numbers having four 3's in base 6.
%C k is in the sequence iff either k == 3 (mod 6) and floor(k/6) is in A043383, or k !== 3 (mod 6) and floor(k/6) is in the sequence. - _Robert Israel_, Jul 24 2018
%H Robert Israel, <a href="/A043384/b043384.txt">Table of n, a(n) for n = 1..10000</a>
%p filter:= n -> numboccur(3, convert(n,base,6))=4:
%p select(filter, [$1..20000]); # _Robert Israel_, Jul 24 2018
%Y Cf. A007092.
%K nonn,base
%O 1,1
%A _Clark Kimberling_