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 A217397 #22 Dec 07 2024 11:11:06 %S A217397 4,40,41,42,43,44,45,46,47,48,49,400,401,402,403,404,405,406,407,408, %T A217397 409,410,411,412,413,414,415,416,417,418,419,420,421,422,423,424,425, %U A217397 426,427,428,429,430,431,432,433,434,435,436,437,438,439,440,441,442 %N A217397 Numbers starting with 4. %C A217397 The lower and upper asymptotic densities of this sequence are 1/36 and 2/9, respectively. - _Amiram Eldar_, Feb 27 2021 %H A217397 Jeremy Gardiner, <a href="/A217397/b217397.txt">Table of n, a(n) for n = 1..1111</a> %H A217397 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>. %F A217397 a(n) = n + (35*10^floor(log_10(9*n-8))-8)/9. - _Alan Michael Gómez Calderón_, May 17 2023 %t A217397 Select[Range[1000], IntegerDigits[#][[1]] == 4 &] (* _T. D. Noe_, Oct 02 2012 *) %o A217397 (Python) %o A217397 def A217397(n): return n+(35*10**(len(str(9*n-8))-1))//9 # _Chai Wah Wu_, Dec 07 2024 %Y A217397 Cf. A000867, A011534. %Y A217397 Subsequences include: A045710, A077329, A077680, A106414, A106424. %Y A217397 Cf. A131835, A217394, A217395, A217398, A217399, A217400, A217401, A217402. %K A217397 nonn,base,easy %O A217397 1,1 %A A217397 _Jeremy Gardiner_, Oct 02 2012