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 A228709 #12 Feb 24 2025 04:36:16 %S A228709 11,13,15,17,19,20,22,24,26,28,31,33,35,37,39,40,42,44,46,48,51,53,55, %T A228709 57,59,60,62,64,66,68,71,73,75,77,79,80,82,84,86,88,91,93,95,97,99, %U A228709 100,102,104,106,108,110,111,112,113,114,115,116,117,118,119,120 %N A228709 Numbers having in decimal representation at least one pair of consecutive digits with the same parity. %H A228709 Reinhard Zumkeller, <a href="/A228709/b228709.txt">Table of n, a(n) for n = 1..10000</a> %F A228709 A228710(a(n)) = 0. %o A228709 (Haskell) %o A228709 a228709 n = a228709_list !! (n-1) %o A228709 a228709_list = filter ((== 0) . a228710) [0..] %Y A228709 Cf. A030141 (complement), A228710, A228722, A228723. %Y A228709 Cf. subsequences: A059708, A010785 (apart from first 10 terms). %K A228709 nonn,base %O A228709 1,1 %A A228709 _Reinhard Zumkeller_, Aug 31 2013