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 A093025 #15 Aug 17 2021 07:03:44 %S A093025 7,12,26,31,45,50,69,74,88,93,106,111,125,130,149,154,168,173,187,192, %T A093025 205,210,229,234,248,253,267,272,286,291,309,314,328,333,347,352,366, %U A093025 371,385,390,408,413,427,432,446,451,465,470,489,494,502,516,521,535 %N A093025 Indices of terms in A093019 with value 5. %C A093025 Integers which require a following 5 to have a valid Luhn mod 10 check digit. %H A093025 Reinhard Zumkeller, <a href="/A093025/b093025.txt">Table of n, a(n) for n = 1..10000</a> %H A093025 John Kilgo, <a href="https://web.archive.org/web/20040627030859/http://www.dotnetjohn.com/articles/articleid97.aspx">Using the Luhn Algorithm</a>, DotNetJohn.com. %H A093025 Webopedia, <a href="http://www.webopedia.com/TERM/L/Luhn_formula.html">Luhn formula</a> %H A093025 Wikipedia, <a href="http://en.wikipedia.org/wiki/Luhn_algorithm">Luhn algorithm</a> %H A093025 <a href="/index/De#decimal_expansion">Index entries for sequences related to decimal expansion of n</a> %F A093025 A093019(a(n)) = 5. - _Reinhard Zumkeller_, Nov 08 2014 %e A093025 12 is in the sequence because A093019(12)=5; 125 has a valid Luhn mod 10 check digit. %o A093025 (Haskell) %o A093025 a093025 n = a093025_list !! (n-1) %o A093025 a093025_list = filter ((== 5) . a093019) [0..] %o A093025 -- _Reinhard Zumkeller_, Nov 08 2014 %Y A093025 Cf. A093017-A093029. %K A093025 easy,nonn,base %O A093025 1,1 %A A093025 _Ray Chandler_, Apr 03 2004 %E A093025 Offset changed by _Reinhard Zumkeller_, Nov 08 2014