%I #13 Jun 20 2021 08:36:20
%S 10,25,40,52,58,60,62,63,65,70,82,97,118,133,145,150,152,153,155,157,
%T 163,175,190,205,220,232,238,240,242,243,245,250,280,292,304,310,312,
%U 314,315,317,322,328,340,346,348,350,351,353,358,360,362,363,365,370
%N Numbers whose base-6 representation has the same nonzero number of 1's and 4's.
%t okQ[n_]:=Module[{dcn6=DigitCount[n,6]},dcn6[[1]]==dcn6[[4]]>0]
%t Select[Range[500],okQ] (* _Harvey P. Dale_, Feb 18 2011 *)
%K nonn,base,easy
%O 1,1
%A _Olivier GĂ©rard_
|