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Numbers whose base-4 representation contains exactly one 0 and no 2's.
1

%I #19 Nov 22 2024 19:43:55

%S 0,4,12,17,19,20,28,49,51,52,60,69,71,77,79,81,83,84,92,113,115,116,

%T 124,197,199,205,207,209,211,212,220,241,243,244,252,277,279,285,287,

%U 309,311,317,319,325,327,333,335,337,339,340,348

%N Numbers whose base-4 representation contains exactly one 0 and no 2's.

%H Robert Israel, <a href="/A045042/b045042.txt">Table of n, a(n) for n = 1..10000</a>

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

%p L:= convert(n,base,4);

%p not member(2,L) and numboccur(0,L)=1

%p end proc:

%p select(filter, [$0..1000]); # _Robert Israel_, Nov 22 2024

%t Select[Range[0,400],DigitCount[#,4,0]==1&&DigitCount[#,4,2]==0&] (* _Harvey P. Dale_, Oct 22 2015 *)

%Y Cf. A007090.

%K nonn,base

%O 1,2

%A _Clark Kimberling_

%E a(1) = 0 inserted by _Georg Fischer_, Jun 28 2019