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 A284557 #14 Jun 29 2022 09:10:50 %S A284557 0,1,2,0,1,0,0,0,2,0,0,1,0,2,0,0,1,2,0,1,0,2,2,2,0,1,1,2,0,2,0,0,2,0, %T A284557 1,2,0,2,2,2,0,1,1,2,1,0,1,1,0,1,2,0,2,1,1,1,0,1,1,2,0,2,0,0,1,2,0,1, %U A284557 2,1,1,1,0,1,1,2,1,0,1,1,0,1,2,0,2,1,1,1,2,0,0,1,2,1,2,2,0,1,2,0,1,0,0,0,1,2,2,0,2,1,2,2,0,1,2,0,2,1,1,1,0 %N A284557 a(n) = A048727(n) mod 3. %H A284557 Antti Karttunen, <a href="/A284557/b284557.txt">Table of n, a(n) for n = 0..8192</a> %H A284557 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %F A284557 a(n) = A048727(n) mod 3. %o A284557 (Scheme) %o A284557 (define (A284557 n) (modulo (A048727 n) 3)) %o A284557 (define (A284557 n) (A284270bi 3 n)) ;; For A284270bi see A284270. %o A284557 (Python) %o A284557 def A284557(n): return (n^ n<<1 ^ n<<2) % 3 # _Chai Wah Wu_, Jun 29 2022 %Y A284557 Row 3 of array A284270 (after the initial zero). %Y A284557 Cf. A048727, A284555 (positions of zeros), A284574, A284575. %K A284557 nonn,base %O A284557 0,3 %A A284557 _Antti Karttunen_, Apr 10 2017