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 A335192 #9 May 26 2020 10:26:00 %S A335192 1,2,4,7,8,6,12,19,23,18,31,39,37,28,56,57,68,60,76,93,103,72,119,133, %T A335192 129,126,164,163,184,146,196,223,239,206,263,283,277,240,328,317,356, %U A335192 336,372,409,431,348,463,489,481,474,548,543,584,510,604,651,679 %N A335192 a(n) is the number of regions inside an n-gon formed by the straight line segments connecting vertex k to vertex 3k mod n. %C A335192 The envelope of the lines form a nephroid. %H A335192 Lars Blomberg, <a href="/A335192/b335192.txt">Table of n, a(n) for n = 3..300</a> %H A335192 Lars Blomberg, <a href="/A335192/a335192.png">Illustration for n = 10</a> %H A335192 Lars Blomberg, <a href="/A335192/a335192_1.png">Illustration for n = 20</a> %H A335192 Lars Blomberg, <a href="/A335192/a335192_2.png">Illustration for n = 40</a> %H A335192 Lars Blomberg, <a href="/A335192/a335192_3.png">Illustration for n = 200</a> %Y A335192 Cf. A335193 (edges), A335194 (vertices), A335195 (n-gons). %K A335192 nonn %O A335192 3,2 %A A335192 _Lars Blomberg_, May 26 2020