A023730 - OEIS

%I #12 Sep 23 2023 15:31:09

%S 2,7,10,11,13,14,17,22,27,32,35,36,38,39,42,47,50,51,53,54,55,56,58,

%T 59,65,66,68,69,70,71,73,74,77,82,85,86,88,89,92,97,102,107,110,111,

%U 113,114,117,122,127,132,135,136,138,139,142,147

%N Numbers with a single 2 in their base 5 expansion.

%H Vincenzo Librandi, <a href="/A023730/b023730.txt">Table of n, a(n) for n = 1..5000</a>

%t Select[ Range[ 150 ], (Count[ IntegerDigits[ #, 5 ], 2 ]==1)& ]

%t Select[Range[200],DigitCount[#,5,2]==1&] (* _Harvey P. Dale_, Sep 23 2023 *)

%K nonn,base,easy

%O 1,1

%A _Olivier Gérard_