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 A259213 #7 Mar 16 2024 13:13:09 %S A259213 1,2,11,38,263,1260,10871,66576,694599,5182960,63738259,561098224, %T A259213 7969169739,80865956192,1304923903919,14998292190464,271341955926479, %U A259213 3484403002454016,69899466563099435,991886288235459072,21861082423955691795,339715268249655012352 %N A259213 Column 2 of triangle A258829. %H A259213 Vaclav Kotesovec, <a href="/A259213/b259213.txt">Table of n, a(n) for n = 0..460</a> %F A259213 a(n) ~ n! * (d*(1-(-1)^n) + 1+(-1)^n)*c/2 * d^n * n^2, where d = 0.8218983778054251105765881248... = 1/(r*sqrt(2)), where r is the root of the equation cot(r)=r and c = 0.986093542875063325007949... . - _Vaclav Kotesovec_, Jun 21 2015, updated Mar 16 2024 %Y A259213 Cf. A258829, A258830. %K A259213 nonn %O A259213 0,2 %A A259213 _Vaclav Kotesovec_, Jun 21 2015