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 A090724 #11 Mar 30 2012 17:34:14
%S A090724 4,1,3,5,3,4,1,3,4,1,3,5,5,2,0,5,2,4,1,6,3,3,0,6,4,2,3,5,2,3,1,4,2,3,
%T A090724 3,5,5,2,0,3,5,3,1,3,5,3,1,6,3,1,0,5,5,2,0,5,2,4,3,5,2,4,2,3,4,3,1,6,
%U A090724 3,3,3,4,5,2,2,3,3,2,0,3,5,2,3,4,4,1,3,5,3,3,0,4,5,2,0,6,2,3,2,6,3,1,2,5,5
%N A090724 Defined in Comments lines.
%C A090724 1. Start with the sequence of final digits of primes (A007652), beginning at 7 so that all members of this sequence will be either 1,3,7, or 9: {7,1,3,7,9,3,9,1,7,1,3,7,3,9,1,7,1,3,...}.
%C A090724 2. Replace all 3's with 6's, all 1's with 3's, all 7's with 5's and all 9's with 4's: {5,3,6,5,4,6,4,3,5,3,6,5,6,4,3,5,3,6, ...}.
%C A090724 3. Subtract (n mod 4) from the n-th member of this sequence (i.e. subtract 1 from the first, 5th, 9th, 13th, ... members, subtract 2 from the 2nd, 6th, 10th, ... members and subtract 3 from the 3rd, 7th, 11th,... members) to get the final sequence: {4,1,3,5,3,4,1,3,4,1,3,5,5,2,0,5,2,4, ...}.
%C A090724 The {0,1,2,3,4,5,6} symbols coded onto the modulo 4 cycle {1,2,3,4} by the prime digits set {1,3,7,9}.
%t A090724 ReplaceAll[Table[Mod[Prime[n+3], 10], {n, 200}], {1->3, 3->6, 7->5, 9->4}]-Table[Mod[n, 4], {n, 200}]
%K A090724 nonn,base,less
%O A090724 4,1
%A A090724 _Roger L. Bagula_, Jan 18 2004