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a(n) = A276086(2*n) mod 4, where A276086 is the primorial base exp-function.
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%I #17 Apr 25 2022 08:11:06

%S 1,3,1,1,3,1,1,3,1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,1,

%T 3,1,1,3,1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,1,3,1,1,3,

%U 1,1,3,1,1,3,1,3,1,3,3,1,3,3,1,3,3,1,3,3,1,3,1,3,1,1,3,1,1,3,1,1,3,1,1,3,1,3

%N a(n) = A276086(2*n) mod 4, where A276086 is the primorial base exp-function.

%H Antti Karttunen, <a href="/A353487/b353487.txt">Table of n, a(n) for n = 0..65537</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%F a(n) = A353486(2*n) = A010873(A276086(2*n)).

%F a(n) = A353516(2*n + 1).

%F a(n) = A353517(1+n). [See comments in A353516 for a proof]

%F For n >= 1, a(n) = (A353517(n) * A353527(n)) mod 4.

%o (PARI)

%o A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };

%o A353487(n) = (A276086(2*n)%4);

%Y Even bisection of A353486. Odd bisection of A353516. Sequence A353517 shifted once left.

%Y Cf. A010873, A276086, A353465, A353466, A353488, A353489, A353527.

%K nonn,base

%O 0,2

%A _Antti Karttunen_, Apr 24 2022