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 A383084 #10 Apr 18 2025 21:51:54 %S A383084 2,2,6,14,147,5743,900487 %N A383084 The number of points in the Euclidean plane that can be determined via a straightedge-and-compass construction using n or fewer lines and circles. %H A383084 Peter Kagey, <a href="/A383084/a383084.png">Illustration of the a(5)=5743 points</a>. %e A383084 For both n = 0 and n = 1, the a(0) = a(1) = 2 points are the initial points: (0,0) and (1,0). %e A383084 For n = 2, the a(2) = 6 points are the two above points along with (-1,0), (2,0), (1/2,-sqrt(3)/2), and (1/2,sqrt(3)/2): %e A383084 (-1,0): formed by intersecting the line between (0,0) and (1,0) with the circle of radius 1 centered at (0,0). %e A383084 (2,0): formed by intersecting the line between (0,0) and (1,0) with the circle of radius 1 centered at (1,0). %e A383084 (1/2,-sqrt(3)/2), and (1/2,sqrt(3)/2): formed by intersecting the circle of radius 1 centered at (0,0) with the circle of radius 1 centered at (1,0). %Y A383084 Cf. A333944, A383082, A383085. %K A383084 nonn,hard,more %O A383084 0,1 %A A383084 _Peter Kagey_, Apr 16 2025