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 A217402 #23 Dec 07 2024 11:11:00 %S A217402 9,90,91,92,93,94,95,96,97,98,99,900,901,902,903,904,905,906,907,908, %T A217402 909,910,911,912,913,914,915,916,917,918,919,920,921,922,923,924,925, %U A217402 926,927,928,929,930,931,932,933,934,935,936,937,938,939,940,941,942 %N A217402 Numbers starting with 9. %C A217402 The lower and upper asymptotic densities of this sequence are 1/81 and 1/9, respectively. - _Amiram Eldar_, Feb 27 2021 %H A217402 Jeremy Gardiner, <a href="/A217402/b217402.txt">Table of n, a(n) for n = 1..1111</a> %H A217402 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>. %F A217402 a(n) = n + (80*10^floor(log_10(9*n-8))-8)/9. - _Alan Michael Gómez Calderón_, May 17 2023 %t A217402 Select[Range[1000], IntegerDigits[#][[1]] == 9 &] (* _T. D. Noe_, Oct 02 2012 *) %o A217402 (Python) %o A217402 def A217402(n): return n+(80*10**(len(str(9*n-8))-1))//9 # _Chai Wah Wu_, Dec 07 2024 %Y A217402 Cf. A000981, A011539. %Y A217402 Subsequences include: A077685, A045715, A106419, A106429, A077334. %Y A217402 Cf. A131835, A217394, A217395, A217397, A217398, A217399, A217400, A217401. %K A217402 nonn,base,easy %O A217402 1,1 %A A217402 _Jeremy Gardiner_, Oct 02 2012