A039403 - OEIS

%I #13 Jun 30 2021 03:54:45

%S 13,31,103,123,130,132,134,135,136,137,138,139,143,153,163,173,183,

%T 193,213,231,301,310,312,314,315,316,317,318,319,321,341,351,361,371,

%U 381,391,413,431,513,531,613,631,713,731,813,831,913,931,1003,1023

%N Numbers whose base-10 representation has the same nonzero number of 1's and 3's.

%t Select[Range[1100],DigitCount[#,10,1]==DigitCount[#,10,3]>0&] (* _Harvey P. Dale_, May 09 2019 *)

%K nonn,base,easy

%O 1,1

%A _Olivier Gérard_