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 A153445 #7 Sep 03 2023 10:23:37 %S A153445 2,15,86,634,3956,18549,69065 %N A153445 Take n points in general position in space; draw all planes through all triples of these points; sequence gives number of connected regions formed. %H A153445 A. Evnin, <a href="http://www.mathnet.ru/eng/mo412">An elementary Introduction to Matroids</a>, Mathematical Education 2 (33) (2005), 2-33 %F A153445 a(n)=1+(n^9-9n^8+6n^7+180n^6-663n^5+369n^4+3536n^3-8964n^2+2952n)/1296 %Y A153445 Cf. A055503 %K A153445 nonn %O A153445 3,1 %A A153445 _Alexander Evnin_, Dec 26 2008