A039605 - OEIS

%I #17 Jul 01 2021 02:50:07

%S 15,37,147,171,180,182,184,185,186,187,188,189,190,191,195,207,219,

%T 231,243,255,267,279,303,325,433,444,446,448,449,450,451,452,453,454,

%U 455,457,481,493,505,517,529,541,553,565,591,613,735,757,879,901,1023

%N Numbers whose base-12 representation has the same nonzero number of 1's and 3's.

%H Robert Israel, <a href="/A039605/b039605.txt">Table of n, a(n) for n = 1..10000</a>

%p filter:= proc(n) local L,v;

%p    L:= convert(n,base,12);

%p    v:= numboccur(1,L);

%p    v > 0 and v = numboccur(3,L)

%p end proc:

%p select(filter, [$1..2000]); # _Robert Israel_, Dec 31 2019

%t Select[Range[1100],DigitCount[#,12,1]==DigitCount[#,12,3]>0&]  (* _Harvey P. Dale_, Apr 21 2011 *)

%K nonn,base,easy

%O 1,1

%A _Olivier Gérard_