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 A353490 #13 Apr 26 2022 07:10:46 %S A353490 1,1,1,2,1,3,1,0,3,1,1,2,1,3,1,0,1,1,1,2,3,3,1,0,1,1,1,2,1,3,1,0,3,1, %T A353490 3,2,1,3,1,0,1,1,1,2,3,3,1,0,3,1,1,2,1,3,3,0,3,1,1,2,1,3,1,0,1,1,1,2, %U A353490 3,3,1,0,1,1,1,2,3,3,1,0,3,1,1,2,1,3,1,0,1,1,1,2,3,3,3,0,1,1,1,2,1,3,1,0,3 %N A353490 The largest proper divisor of n, reduced modulo 4, with a(1) = 1. %H A353490 Antti Karttunen, <a href="/A353490/b353490.txt">Table of n, a(n) for n = 1..65537</a> %F A353490 a(n) = A010873(A032742(n)). %o A353490 (PARI) %o A353490 A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1])); %o A353490 A353490(n) = (A032742(n)%4); %o A353490 (Python) %o A353490 from sympy import factorint %o A353490 def a(n): return 1 if n==1 else (n//min(factorint(n)))%4 %o A353490 print([a(n) for n in range(1, 106)]) # _Michael S. Branicky_, Apr 26 2022 %Y A353490 Cf. A032742, A353491, A353492. %K A353490 nonn %O A353490 1,4 %A A353490 _Antti Karttunen_, Apr 22 2022