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 A272913 #26 Sep 08 2022 08:46:16 %S A272913 0,0,6912,2073600,361267200,48771072000,5665247723520,595732271726592, %T A272913 58357447026278400,5420989989833932800,483204292920999936000, %U A272913 41671538221507034480640,3497929581885972295974912,287077554068924493987840000,23115688495680026711162880000 %N A272913 a(n) = 3*2^(2*n-1)*(n-1)*n^3*binomial(2*n,n)^2, a closed form for a triple binomial sum involving absolute values. %C A272913 See Theorem 6 of Brent et al. article. %C A272913 a(n) is divisible by 48^2. %H A272913 Vincenzo Librandi, <a href="/A272913/b272913.txt">Table of n, a(n) for n = 0..500</a> %H A272913 Richard P. Brent, Hideyuki Ohtsuka, Judy-anne H. Osborn, Helmut Prodinger, <a href="http://arxiv.org/abs/1411.1477">Some binomial sums involving absolute values</a>, arXiv:1411.1477 [math.CO], 2016, page 11. %F A272913 a(n) = Sum_{i=-n..n} (Sum_{j=-n..n} (Sum_{k=-n..n} binomial(2*n, n+i)*binomial(2*n, n+j)*binomial(2*n, n+k)*|(i^2-j^2)*(i^2-k^2)*(j^2-k^2)|)). %F A272913 G.f.: 6912*x^2*(2F1(5/2, 5/2, 2, 64*x) + 100*x*2F1(7/2, 7/2, 3, 64*x)), where 2F1() is the Gauss hypergeometric function. %F A272913 D-finite with recurrence (n-2)*(n-1)^2*a(n) -16*n*(2*n-1)^2*a(n-1)=0. - _R. J. Mathar_, Feb 08 2021 %t A272913 Table[3 2^(2 n - 1) (n - 1) n^3 Binomial[2 n, n]^2, {n, 0, 20}] %o A272913 (PARI) vector(20, n, n--; 3*2^(2*n-1)*(n-1)*n^3*binomial(2*n,n)^2) %o A272913 (Sage) [3*2^(2*n-1)*(n-1)*n^3*binomial(2*n, n)^2 for n in range(20)] %o A272913 (Magma) [3*2^(2*n-1)*(n-1)*n^3*Binomial(2*n,n)^2: n in [0..20]]; %Y A272913 Cf. A254408, A268147, A268148, A268149, A268150, A268151, A268152, A269877. %K A272913 nonn,easy %O A272913 0,3 %A A272913 _Bruno Berselli_, May 10 2016