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%I #14 Oct 13 2023 11:49:56
%S 1,3,17,19,49,51,273,275,305,307,785,787,817,819,4369,4371,4401,4403,
%T 4881,4883,4913,4915,12561,12563,12593,12595,13073,13075,13105,13107,
%U 69905,69907,69937,69939,70417,70419,70449,70451
%N Numbers whose set of base-16 digits is {1,3}.
%H Vincenzo Librandi, <a href="/A032923/b032923.txt">Table of n, a(n) for n = 1..1000</a>
%t Flatten[Table[FromDigits[#,16]&/@Tuples[{1,3},n],{n,5}]] (* _Vincenzo Librandi_, Jun 03 2012 *)
%o (Magma) [n: n in [1..75000] | Set(IntegerToSequence(n, 16)) subset {1, 3}]; // _Vincenzo Librandi_, Jun 03 2012
%o (Python)
%o def A032923(n): return (int(bin(m:=n+1)[3:],16)<<1) + ((1<<(m.bit_length()-1<<2))-1)//15 # _Chai Wah Wu_, Oct 13 2023
%K nonn,base
%O 1,2
%A _Clark Kimberling_
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