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 A214445 #11 Apr 27 2023 10:13:55 %S A214445 1,-6,350,-56364,17824950,-9334057876,7308698191340,-7997684730384600, %T A214445 11655857682806336550,-21824608434847162167300, %U A214445 51054382673481634917970500,-145916894745749901373155951720,500306549034304293474784779805500,-2026855002861172152744641068895033544 %N A214445 a(n) = Euler(2*n)*binomial(4*n,2*n). %C A214445 Central column of the nonzero coefficients of the Swiss-Knife polynomials, a(n) = A153641(4*n, 2*n). %F A214445 a(n) = (-1)^n * A086646(2n,n). - _Alois P. Heinz_, Apr 27 2023 %o A214445 (Sage) %o A214445 def A214445(n) : return binomial(4*n,2*n)*euler_number(2*n) %Y A214445 Cf. A086646, A153641. %K A214445 sign %O A214445 0,2 %A A214445 _Peter Luschny_, Jul 18 2012