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 A353631 #10 May 05 2022 10:04:44
%S A353631 1,1,1,3,3,3,1,1,1,3,3,3,1,1,1,1,1,1,3,3,3,1,1,1,3,3,3,1,1,1,1,1,1,3,
%T A353631 3,3,1,1,1,3,3,3,1,1,1,1,1,1,3,3,3,1,1,1,3,3,3,1,1,1,1,1,1,3,3,3,1,1,
%U A353631 1,3,3,3,1,1,1,1,1,1,3,3,3,1,1,1,3,3,3,1,1,1,1,1,1,3,3,3,1,1,1,3,3,3,1,1,1,1
%N A353631 Arithmetic derivative of primorial base exp-function, reduced modulo 4, computed for odd numbers.
%C A353631 Run lengths seem to be given by sequence 3, 3, 3, 3, 6, 3, 3, 3, 6, 3, 3, 3, 6, 3, 3, 3, 6, 3, 3, 3, 6, etc., with initially starting with four runs of length 3, followed by a run of length 6, after which periodically with always three runs of length three followed by one run of six terms (that are always 1's).
%H A353631 Antti Karttunen, <a href="/A353631/b353631.txt">Table of n, a(n) for n = 0..65537</a>
%H A353631 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%F A353631 a(n) = A353630(2*n+1) = A010873(A327860(2*n+1)).
%o A353631 (PARI)
%o A353631 A353630(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= (p^e); s += (e/p); n = n\p; p = nextprime(1+p)); ((s*m)%4); };
%o A353631 A353631(n) = A353630(n+n+1);
%Y A353631 Odd bisection of A353630.
%Y A353631 Cf. A010873, A327860, A353632.
%Y A353631 Cf. also A353641.
%K A353631 nonn,base
%O A353631 0,4
%A A353631 _Antti Karttunen_, May 01 2022