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 A174209 #12 Nov 26 2015 05:52:22 %S A174209 10,1,2,13,4,15,6,17,8,19,2,2,2,2,2,30,1,32,3,4,35,6,37,8,39,4,4,4,4, %T A174209 4,50,1,52,3,54,5,6,57,8,59,6,6,6,6,6,70,1,72,3,74,5,76,7,8,79,8,8,8, %U A174209 8,8,90,1,92,3,94,5,96,7,98,9,0,10,1,0,1,0,1,0,1,0,1,11,12,13,14,15,16,17 %N A174209 In the sequence of natural numbers, moving left to right, delete 1st, 3rd, 5th, 7th etc occurrence of each of the ten digits. %e A174209 Starting from %e A174209 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,1,20,21,22,23,24,25,26,27,28,29,.. %e A174209 Delete odd occurrences of digit 0 (replaced by ~): %e A174209 ,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,2~,21,22,23,24,25,26,27,28,29,.. %e A174209 Delete odd occurrences of digit 1 (replaced by ~): %e A174209 ,~,2,3,4,5,6,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,2~,2~,22,23,24,25,26,27,28,29 ,.. %e A174209 Delete odd occurrences of digit 2 (replaced by ~): %e A174209 ,~,~,3,4,5,6,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~3,24,~5,26,~7,28,~9 ,.. %e A174209 Delete odd occurrences of digit 3 (replaced by ~): %e A174209 ,~,~,~,4,5,6,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,24,~5,26,~7,28,~9,.. %e A174209 Delete odd occurrences of digit 4 (replaced by ~): %e A174209 ,~,~,~,~,5,6,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~5,26,~7,28,~9,.. %e A174209 Delete odd occurrences of digit 5 (replaced by ~): %e A174209 ,~,~,~,~,~,6,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~~,26,~7,28,~9,.. %e A174209 Delete odd occurrences of digit 6 (replaced by ~): %e A174209 ,~,~,~,~,~,~,7,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~~,2~,~7,28,~9,.. %e A174209 Delete odd occurrences of digit 7 (replaced by ~): %e A174209 ,~,~,~,~,~,~,~,8,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~~,2~,~~,28,~9,.. %e A174209 Delete odd occurrences of digit 8 (replaced by ~): %e A174209 ,~,~,~,~,~,~,~,~,9,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~~,2~,~~,2~,~9,.. %e A174209 Delete odd occurrences of digit 9 (replaced by ~): %e A174209 ,~,~,~,~,~,~,~,~,~,10,~1,~2,13,~4,15,~6,17,~8,19,~~,2~,~2,~~,2~,~~,2~,~~,2~,~~,.. %e A174209 The residual digits define the sequence: 10, 1, 2, 13, 4, 15, 6, 17, 8, 19, 2, 2, 2, 2, 2,.... %Y A174209 Cf. A174203, A174204, A174205, A174206, A174207, A174208, A174210. %K A174209 easy,nonn,base %O A174209 0,1 %A A174209 _Paolo P. Lava_ & _Giorgio Balzarotti_, Mar 15 2010