cp's OEIS Frontend

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.

A333944 Constructibility sequence, the number of points constructed by straightedge and compass after successive stages of forming all possible lines, circles, and intersection points, beginning with 2 points.

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%I A333944 #21 Aug 20 2022 02:22:32
%S A333944 2,6,203,1723816861
%N A333944 Constructibility sequence, the number of points constructed by straightedge and compass after successive stages of forming all possible lines, circles, and intersection points, beginning with 2 points.
%C A333944 The fourth value was computed by Teofil Camarasu, taking 6 days of computer time performing exact algebraic computations (see link to Mathematics Stack Exchange).
%C A333944 Note that circles are formed only by specifying an already existing segment as radius (so we have collapsible compasses only).
%D A333944 Joel David Hamkins, Lectures on the Philosophy of Mathematics, MIT Press, 2020, chapter 4. (in press)
%H A333944 Joel David Hamkins, Mathematics Stack Exchange question, <a href="https://math.stackexchange.com/q/3377988/413">What is the next number on the constructibility sequence? And what is the asymptotic growth?</a>, including answers by Teofil Camarasu and Pace Nielsen.
%H A333944 Joel David Hamkins, Illustrating the construction sequence: <a href="/A333944/a333944.jpg">Begin with 2 points, stage 1</a>, <a href="/A333944/a333944_1.jpg">6 points at stage 2</a>, <a href="/A333944/a333944_2.jpg">203 points at stage 3</a>.
%e A333944 Begin with 2 points A and B. Construct the line containing them and the two circles having AB as radius; these intersect at four additional points, making 6 points in all. Using these 6 points, one may construct 9 new lines and 14 new circles, leading to 203 intersection points in all.
%K A333944 nonn,hard,more
%O A333944 1,1
%A A333944 _Joel David Hamkins_, Apr 11 2020