OFFSET
1,1
COMMENTS
The asymptotic density of this sequence is log_10(5/4) = 0.096910...
MAPLE
x := 1:
L := []:
for n from 0 to 10^3 do
if 4 <= x and x < 5 then
L := [op(L), n]
fi;
x := 2*x;
if x > 10 then
x := (1/10)*x fi;
od:
L;
MATHEMATICA
Select[Range[550], IntegerDigits[2^#][[1]] == 4 &] (* Amiram Eldar, Nov 12 2023 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Martin Renner, Nov 12 2023
STATUS
approved