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A319563
Let f(1) = 1, f(2) = 1 + i (where i denotes the imaginary unit), and for n > 1, f(n+1) is the Gaussian integer in the first quadrant (with positive real part and nonnegative imaginary part) with least modulus and sharing a prime factor with f(n) (in case of a tie, minimize the imaginary part); a(n) = the imaginary part of f(n).
2
0, 1, 0, 2, 1, 2, 4, 3, 1, 2, 0, 3, 0, 0, 1, 3, 6, 5, 2, 4, 4, 3, 4, 8, 5, 1, 2, 2, 0, 3, 6, 3, 4, 6, 1, 5, 7, 3, 5, 10, 7, 2, 4, 0, 6, 5, 6, 12, 7, 1, 2, 4, 7, 1, 4, 8, 2, 6, 9, 8, 1, 5, 10, 9, 4, 8, 3, 0, 9, 7, 0, 0, 0, 7, 6, 8, 2, 10, 5, 7, 14, 9, 2, 4, 1
OFFSET
1,4
COMMENTS
See A319561 for the square of the modulus of f and additional comments.
LINKS
PROG
(PARI) See Links section.
CROSSREFS
Cf. A319561.
Sequence in context: A262876 A263045 A333442 * A201912 A201908 A337712
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Sep 23 2018
STATUS
approved