This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A097415 #17 Feb 16 2025 08:32:54 %S A097415 53,63,73,83,93,156,166,176,186,249,259,269,279,289,352,362,372,382, %T A097415 445,455,465,475,485,548,558,568,578,641,651,661,671,734,744,754,764, %U A097415 774,837,847,857,867,930,940,950,960,970,1033,1043,1053,1063,1126 %N A097415 Values of k such that the first digit of 2^k is 9. %C A097415 The asymptotic density of this sequence is 1 - log_10(9) = 0.045757... (A104140). - _Amiram Eldar_, Jan 27 2021 %H A097415 Amiram Eldar, <a href="/A097415/b097415.txt">Table of n, a(n) for n = 1..10000</a> %H A097415 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GelfandsQuestion.html">Gelfand's Question</a>. %t A097415 Select[Range[1200],IntegerDigits[2^#][[1]]==9&] (* _Harvey P. Dale_, Nov 30 2019 *) %Y A097415 Cf. A000079, A104140. %K A097415 nonn,base %O A097415 1,1 %A A097415 _Eric W. Weisstein_, Aug 16 2004