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 A259327 #5 Aug 16 2015 17:29:24 %S A259327 1,1,18,141891750,17844701940490283892633600000, %T A259327 59757436204078657410908164193971177467471236322918735173920946651136000000000000 %N A259327 Ceiling of ((2^n)!)/(4^n*(n!)^2). %H A259327 C. S. Lorens, <a href="http://dx.doi.org/10.1109/PGEC.1964.263724">Invertible Boolean functions</a>, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541. %H A259327 C. S. Lorens, <a href="/A000722/a000722.pdf">Invertible Boolean functions</a>, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541. [Annotated scan of page 530 only] %K A259327 nonn %O A259327 1,3 %A A259327 _N. J. A. Sloane_, Jun 24 2015