This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A373810 #31 Jul 09 2025 05:04:58 %S A373810 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, %T A373810 9,9,9,9,9,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,12,12,12,12, %U A373810 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 %N 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). %H A373810 Max Alekseyev, <a href="/A373810/b373810.txt">Table of n, a(n) for n = 1..455</a> %H A373810 Max Alekseyev, <a href="https://github.com/maxale/oeis/blob/main/a3738xx_lines_covering_points.sage">Sage program for lines covering points</a>, Github, Aug 19 2024 %H A373810 N. J. A. Sloane, <a href="https://www.youtube.com/watch?v=3RAYoaKMckM">A Nasty Surprise in a Sequence and Other OEIS Stories</a>, Experimental Mathematics Seminar, Rutgers University, Oct 10 2024, Youtube video; <a href="https://sites.math.rutgers.edu/~zeilberg/expmath/sloane85BD.pdf">Slides</a> [Mentions this sequence] %Y A373810 Cf. A000010, A375499, A373813, A373815 (RUNS). %K A373810 nonn %O A373810 1,3 %A A373810 _Rémy Sigrist_ and _N. J. A. Sloane_, Aug 18 2024 %E A373810 Terms a(19) onward from _Max Alekseyev_, Aug 18 2024