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 A130032 #42 Feb 11 2024 02:47:57
%S A130032 1,1,3,21,273,5733,177723,7642089,435599073,31798732329,2893684641939,
%T A130032 321198995255229,42719466368945457,6706956219924436749,
%U A130032 1227372988246171925067,258975700519942276189137,62413143825306088561582017,17038788264308562177311890641
%N A130032 Row sums of unsigned triangle A129467.
%H A130032 G. C. Greubel, <a href="/A130032/b130032.txt">Table of n, a(n) for n = 0..250</a>
%H A130032 M. Bruschi, F. Calogero and R. Droghei, <a href="http://dx.doi.org/10.1088/1751-8113/40/14/005">Proof of certain Diophantine conjectures and identification of remarkable classes of orthogonal polynomials</a>, J. Physics A, 40(2007), pp. 3815-3829.
%F A130032 a(n) = Sum_{m=0..n} |A129467(n,m)| for n >= 0.
%F A130032 a(n) = Sum_{j=0..n-1} |A130559(n-1, j)|, n >= 1.
%F A130032 For n > 0, a(n) = n! * Product_{k=1..n} [Gamma(k + 1/k)/Gamma(k - 1 + 1/k)]. - _Gerald McGarvey_, Nov 05 2007
%F A130032 a(n) = Product_{k=0..n} (k^2 - k + 1). - _Gary Detlefs_, Mar 04 2012
%F A130032 a(n) ~ c*n!*(n-1)! for c = Product_{k>=1} (1+1/(k^2+k)) = 2.428189792... [_Charles R Greathouse IV_, Mar 04 2012], c = cosh(sqrt(3)*Pi/2)/Pi. - _Vaclav Kotesovec_, Aug 24 2016
%F A130032 G.f.: 1 + x + 3*x^2/(Q(0)-3*x), where Q(k) = 1 + x*(k^2+3*k+3) - x*(k^2+5*k+7)/Q(k+1) ; (continued fraction). - _Sergei N. Gladkovskii_, Dec 15 2013
%t A130032 Round@Table[Cosh[Sqrt[3] Pi/2] Gamma[n + 1/2 + I Sqrt[3]/2] Gamma[n + 1/2 - I Sqrt[3]/2]/Pi, {n, 0, 20}] (* _Vladimir Reshetnikov_, Aug 23 2016 *)
%t A130032 Product[k^2-k+1, {k,0,Range[0,30]}] (* _G. C. Greubel_, Feb 10 2024 *)
%o A130032 (PARI) a(n)=prod(k=1,n,k^2-k+1) \\ _Charles R Greathouse IV_, Mar 04 2012
%o A130032 (Magma) [1] cat [n le 1 select 1 else (n^2-n+1)*Self(n-1): n in [1..30]]; // _G. C. Greubel_, Feb 10 2024
%o A130032 (SageMath)
%o A130032 def A130032(n): return 1 if n<2 else (n^2-n+1)*A130032(n-1)
%o A130032 [A130032(n) for n in range(31)] # _G. C. Greubel_, Feb 10 2024
%Y A130032 Cf. A130031 (signed row sums), A130559 (unsigned row sums).
%K A130032 nonn,easy
%O A130032 0,3
%A A130032 _Wolfdieter Lang_, May 04 2007
%E A130032 Definition corrected by _Wolfdieter Lang_, Jun 04 2010