cp's OEIS Frontend

A371098 a(n) = gcd(2n+1, A276086(2n+1)), where A276086 is the primorial base exp-function.

%I A371098 #8 Mar 10 2024 20:04:34
%S A371098 1,3,1,1,3,1,1,15,1,1,3,1,25,3,1,1,3,7,1,3,1,1,15,1,7,3,1,5,3,1,1,21,
%T A371098 1,1,3,1,1,75,7,1,3,1,5,3,1,7,3,1,1,3,1,1,105,1,1,3,1,5,3,7,1,3,1,1,3,
%U A371098 1,7,15,1,1,3,1,5,147,1,1,3,1,1,3,7,1,15,1,1,3,1,175,3,1,1,3,1,1,21,1,1,15,1,1,3
%N A371098 a(n) = gcd(2n+1, A276086(2n+1)), where A276086 is the primorial base exp-function.
%H A371098 Antti Karttunen, <a href="/A371098/b371098.txt">Table of n, a(n) for n = 0..16384</a>
%H A371098 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%F A371098 a(n) = gcd(2n+1, A276086(2n+1)) = gcd(2n+1, A276086(2n)).
%F A371098 a(n) = A324198(2n+1).
%t A371098 f[x_] := Block[{m, i, n = x, p}, m = i = 1; While[n > 0, p = Prime[i]; m *= p^Mod[n, p]; n = Quotient[n, p]; i++]; m]; Array[GCD[2 # + 1, f[2 #]] &, 120, 0] (* _Michael De Vlieger_, Mar 10 2024 *)
%o A371098 (PARI)
%o A371098 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A371098 A371098(n) = gcd(n+n+1, A276086(n+n));
%Y A371098 Odd bisection of A324198.
%Y A371098 Cf. A276086.
%K A371098 nonn
%O A371098 0,2
%A A371098 _Antti Karttunen_, Mar 10 2024