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 A353517 #11 Apr 25 2022 08:11:10
%S A353517 1,1,3,1,1,3,1,1,3,1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,
%T A353517 1,3,1,1,3,1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,1,3,1,1,
%U A353517 3,1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,1,3,1,1,3,1,1,3,1,1,3,1
%N A353517 The largest proper divisor of A276086(2*n) reduced modulo 4, where A276086(n) the primorial base exp-function.
%H A353517 Antti Karttunen, <a href="/A353517/b353517.txt">Table of n, a(n) for n = 0..65537</a>
%H A353517 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%F A353517 a(n) = A353516(2*n) = A010873(A324895(2*n)).
%F A353517 For n >= 1, a(n) = (A353487(n) * A353527(n)) mod 4.
%F A353517 For n >= 1, a(n) = A353487(n-1). [See A353516 for a proof]
%o A353517 (PARI)
%o A353517 A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
%o A353517 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A353517 A324895(n) = A032742(A276086(n));
%o A353517 A353517(n) = (A324895(2*n)%4);
%Y A353517 Even bisection of A353516. Sequence A353487 shifted one term right.
%Y A353517 Cf. A010873, A032742, A276086, A324895, A353527.
%K A353517 nonn
%O A353517 0,3
%A A353517 _Antti Karttunen_, Apr 24 2022