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 A246606 #14 Apr 27 2024 16:39:43 %S A246606 1,4,78,3216,229080,25022880,3884393520,812752093440,220448163358080, %T A246606 75225258805132800,31537353006189676800,15933924342019634227200, %U A246606 9548252826112300306406400,6695627848564821490753228800,5431772705577464891946292992000,5047432593984519350928894369792000 %N A246606 Central terms of the triangle A116853. %C A246606 a(n) = A116853(2*n,n). %H A246606 Reinhard Zumkeller, <a href="/A246606/b246606.txt">Table of n, a(n) for n = 1..200</a> %F A246606 a(n) = (2*n - 1)!*hypergeom([1 - n], [1 - 2*n], -1). - _Peter Luschny_, Nov 04 2018 %F A246606 Conjecture: D-finite with recurrence +(-2*n+3)*a(n) +4*(n-1)*(2*n^2-4*n+1)*a(n-1) +(n-1)*(n-2)*(2*n-1)*a(n-2)=0. - _R. J. Mathar_, Jul 01 2022 %F A246606 a(n) ~ sqrt(Pi) * 2^(2*n) * n^(2*n - 1/2) / exp(2*n + 1/2). - _Vaclav Kotesovec_, Mar 08 2023 %p A246606 a := n -> (2*n - 1)!*hypergeom([1 - n], [1 - 2*n], -1): %p A246606 seq(simplify(a(n)), n=1..15); # _Peter Luschny_, Nov 04 2018 %o A246606 (Haskell) %o A246606 a246606 n = a116853 (2 * n - 1) n %Y A246606 Cf. A000142, A116853. %K A246606 nonn %O A246606 1,2 %A A246606 _Reinhard Zumkeller_, Aug 31 2014