This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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
 2, 5, 13, 9, 1129, 29, 17, 651250309, 5, 13, 17, 29, 37, 16767128453, 41, 133981, 2236369, 61, 45293, 22481146745713207066897, 12041, 653, 51908348513173, 121, 11821, 779353 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The real and imaginary parts of f are respectively given by A320103 and A320104. This sequence is a complex variant of the Euclid-Mullin sequence (A000945). All terms belong to A055025. LINKS Rémy Sigrist, PARI program for A319920 FORMULA a(n) = A320103(n)^2 + A320104(n)^2. PROG (PARI) See Links section. CROSSREFS Cf. A000945, A055025, A320103, A320104. Sequence in context: A139023 A241758 A173620 * A166134 A067365 A189993 Adjacent sequences:  A319917 A319918 A319919 * A319921 A319922 A319923 KEYWORD nonn,hard AUTHOR Rémy Sigrist, Oct 01 2018 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 15 16:29 EDT 2019. Contains 325049 sequences. (Running on oeis4.)