cp's OEIS Frontend

A319920 Let f(1) = 1 + i (where i denotes the imaginary unit) and for n > 0, f(n+1) is the Gaussian prime in the first quadrant (with positive real part and nonnegative imaginary part) with least modulus that divides 1 + Product_{k=1..n} f(k) (in case of a tie minimize the imaginary part); a(n) is the square of the modulus of f(n).

%I A319920 #9 Oct 08 2018 08:07:27
%S A319920 2,5,13,9,1129,29,17,651250309,5,13,17,29,37,16767128453,41,133981,
%T A319920 2236369,61,45293,22481146745713207066897,12041,653,51908348513173,
%U A319920 121,11821,779353
%N A319920 Let f(1) = 1 + i (where i denotes the imaginary unit) and for n > 0, f(n+1) is the Gaussian prime in the first quadrant (with positive real part and nonnegative imaginary part) with least modulus that divides 1 + Product_{k=1..n} f(k) (in case of a tie minimize the imaginary part); a(n) is the square of the modulus of f(n).
%C A319920 The real and imaginary parts of f are respectively given by A320103 and A320104.
%C A319920 This sequence is a complex variant of the Euclid-Mullin sequence (A000945).
%C A319920 All terms belong to A055025.
%H A319920 Rémy Sigrist, <a href="/A319920/a319920.gp.txt">PARI program for A319920</a>
%F A319920 a(n) = A320103(n)^2 + A320104(n)^2.
%o A319920 (PARI) See Links section.
%Y A319920 Cf. A000945, A055025, A320103, A320104.
%K A319920 nonn,hard
%O A319920 1,1
%A A319920 _Rémy Sigrist_, Oct 01 2018