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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). 3

%I #9 Oct 08 2018 08:07:27

%S 2,5,13,9,1129,29,17,651250309,5,13,17,29,37,16767128453,41,133981,

%T 2236369,61,45293,22481146745713207066897,12041,653,51908348513173,

%U 121,11821,779353

%N 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 The real and imaginary parts of f are respectively given by A320103 and A320104.

%C This sequence is a complex variant of the Euclid-Mullin sequence (A000945).

%C All terms belong to A055025.

%H Rémy Sigrist, <a href="/A319920/a319920.gp.txt">PARI program for A319920</a>

%F a(n) = A320103(n)^2 + A320104(n)^2.

%o (PARI) See Links section.

%Y Cf. A000945, A055025, A320103, A320104.

%K nonn,hard

%O 1,1

%A _Rémy Sigrist_, Oct 01 2018

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Last modified August 4 12:14 EDT 2024. Contains 374920 sequences. (Running on oeis4.)