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A373810
a(n) is the smallest number of straight lines needed to intersect all points (k, phi(k)) for k = 1..n (where phi is the Euler totient function A000010).
5
1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 17
OFFSET
1,3
LINKS
Max Alekseyev, Sage program for lines covering points, Github, Aug 19 2024
N. J. A. Sloane, A Nasty Surprise in a Sequence and Other OEIS Stories, Experimental Mathematics Seminar, Rutgers University, Oct 10 2024, Youtube video; Slides [Mentions this sequence]
CROSSREFS
Sequence in context: A301461 A172471 A373811 * A375433 A046155 A026819
KEYWORD
nonn
AUTHOR
Rémy Sigrist and N. J. A. Sloane, Aug 18 2024.
EXTENSIONS
Terms a(19) onward from Max Alekseyev, Aug 18 2024
STATUS
approved