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 A319771 Let f(1) = 1, f(2) = 1 + i (where i denotes the imaginary unit), f(3) = 2 + i, and for n > 2, f(n+1) is the Gaussian integer in the first quadrant (with positive real part and nonnegative imaginary part) with least modulus and sharing at least one prime factor with f(n-1) but none with f(n) (in case of a tie, minimize the imaginary part); a(n) = the real part of f(n). 2
 1, 1, 2, 2, 5, 2, 1, 1, 4, 4, 3, 4, 3, 3, 6, 2, 3, 3, 4, 5, 3, 2, 1, 7, 4, 8, 5, 2, 1, 4, 2, 7, 6, 1, 3, 9, 6, 2, 1, 12, 6, 2, 2, 9, 7, 6, 4, 11, 7, 10, 3, 5, 5, 5, 15, 8, 9, 8, 9, 7, 6, 1, 6, 13, 5, 8, 6, 8, 4, 9, 1, 4, 4, 3, 1, 11, 5, 3, 14, 7, 8, 7, 9, 14 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS See A319770 for the square of the modulus of f and additional comments. LINKS Rémy Sigrist, Table of n, a(n) for n = 1..10000 CROSSREFS Cf. A319770. Sequence in context: A068762 A326914 A155679 * A021448 A229709 A242277 Adjacent sequences:  A319768 A319769 A319770 * A319772 A319773 A319774 KEYWORD nonn AUTHOR Rémy Sigrist, Sep 27 2018 STATUS approved

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Last modified January 22 07:38 EST 2021. Contains 340360 sequences. (Running on oeis4.)