A097415 - OEIS

%I #16 Jan 27 2021 05:35:53

%S 53,63,73,83,93,156,166,176,186,249,259,269,279,289,352,362,372,382,

%T 445,455,465,475,485,548,558,568,578,641,651,661,671,734,744,754,764,

%U 774,837,847,857,867,930,940,950,960,970,1033,1043,1053,1063,1126

%N Values of k such that the first digit of 2^k is 9.

%C The asymptotic density of this sequence is 1 - log_10(9) = 0.045757... (A104140). - _Amiram Eldar_, Jan 27 2021

%H Amiram Eldar, <a href="/A097415/b097415.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GelfandsQuestion.html">Gelfand's Question</a>.

%t Select[Range[1200],IntegerDigits[2^#][[1]]==9&] (* _Harvey P. Dale_, Nov 30 2019 *)

%Y Cf. A000079, A104140.

%K nonn,base

%O 1,1

%A _Eric W. Weisstein_, Aug 16 2004