%I #18 Sep 08 2022 08:44:52
%S 0,1,2,3,4,5,6,7,10,11,12,13,14,15,17,18,22,23,24,26,27,30,31,32,34,
%T 36,38,43,46,55,62,65,66,71
%N Numbers k such that 2^k does not contain the digit 5 (probably finite).
%t Join[{0}, Select[Range@10000, FreeQ[IntegerDigits[2^#], 5] &]] (* _Vincenzo Librandi_, May 07 2015 *)
%t Select[Range[0,80],DigitCount[2^#,10,5]==0&] (* _Harvey P. Dale_, Dec 24 2018 *)
%o (Magma) [n: n in [0..1000] | not 5 in Intseq(2^n) ]; // _Vincenzo Librandi_, May 07 2015
%Y Cf. similar sequences listed in A035064.
%K nonn,base
%O 1,3
%A _Patrick De Geest_, Nov 15 1998
%E Initial 0 inserted by _Vincenzo Librandi_, May 07 2015