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 A320996 #3 Oct 26 2018 13:28:52 %S A320996 1,1,0,-2,-5,-9,-14,-34,-69,-125,-209,-461 %N A320996 Extremal values of Euler characteristics of polytopes. %H A320996 H. Hadwiger and P. Mani, <a href="https://doi.org/10.1016/0097-3165(74)90099-5">On polyhedra with extremal Euler characteristic</a>, J. Combin. Theory, A 17 (1974), 345-349. See p. 346. %Y A320996 Cf. A006481. %K A320996 sign,more %O A320996 1,4 %A A320996 _N. J. A. Sloane_, Oct 26 2018