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 A217400 #23 Dec 07 2024 11:10:43 %S A217400 7,70,71,72,73,74,75,76,77,78,79,700,701,702,703,704,705,706,707,708, %T A217400 709,710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725, %U A217400 726,727,728,729,730,731,732,733,734,735,736,737,738,739,740,741,742 %N A217400 Numbers starting with 7. %C A217400 The lower and upper asymptotic densities of this sequence are 1/63 and 5/36, respectively. - _Amiram Eldar_, Feb 27 2021 %H A217400 Jeremy Gardiner, <a href="/A217400/b217400.txt">Table of n, a(n) for n = 1..1111</a> %H A217400 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>. %F A217400 a(n) = n + (62*10^floor(log_10(9*n-8))-8)/9. - _Alan Michael Gómez Calderón_, May 17 2023 %t A217400 Select[Range[1000], IntegerDigits[#][[1]] == 7 &] (* _T. D. Noe_, Oct 02 2012 *) %o A217400 (Python) %o A217400 def A217400(n): return n+(62*10**(len(str(9*n-8))-1))//9 # _Chai Wah Wu_, Dec 07 2024 %Y A217400 Cf. A000870, A011537. %Y A217400 Subsequences include: A045713, A077332, A077683, A106417, A106427. %Y A217400 Cf. A131835, A217394, A217395, A217397, A217398, A217399, A217401, A217402. %K A217400 nonn,base,easy %O A217400 1,1 %A A217400 _Jeremy Gardiner_, Oct 02 2012