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 A008385 #37 Dec 13 2023 10:53:10
%S A008385 1,30,240,1010,2970,7002,14240,26070,44130,70310,106752,155850,220250,
%T A008385 302850,406800,535502,692610,882030,1107920,1374690,1687002,2049770,
%U A008385 2468160,2947590,3493730,4112502,4810080,5592890,6467610,7441170,8520752
%N A008385 Coordination sequence for A_5 lattice.
%H A008385 T. D. Noe, <a href="/A008385/b008385.txt">Table of n, a(n) for n = 0..1000</a>
%H A008385 M. Baake and U. Grimm, <a href="https://arxiv.org/abs/cond-mat/9706122">Coordination sequences for root lattices and related graphs</a>, arXiv:cond-mat/9706122, 1997; Zeit. f. Kristallographie, 212 (1997), 253-256.
%H A008385 R. Bacher, P. de la Harpe and B. Venkov, <a href="https://doi.org/10.1016/S0764-4442(97)83542-2">Séries de croissance et séries d'Ehrhart associées aux réseaux de racines</a>, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.
%H A008385 J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (<a href="http://neilsloane.com/doc/Me220.pdf">pdf</a>).
%H A008385 M. O'Keeffe, <a href="http://dx.doi.org/10.1524/zkri.1995.210.12.905">Coordination sequences for lattices</a>, Zeit. f. Krist., 210 (1995), 905-908.
%H A008385 M. O'Keeffe, <a href="/A008527/a008527.pdf">Coordination sequences for lattices</a>, Zeit. f. Krist., 210 (1995), 905-908. [Annotated scanned copy]
%H A008385 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A008385 a(n) = (21*n^4 + 35*n^2 + 4)/2, a(0) = 1.
%F A008385 G.f.: (1+x)*(1+24*x+76*x^2+24*x^3+x^4)/(1-x)^5. - _Colin Barker_, Apr 13 2012
%F A008385 E.g.f.: (1/2)*(-2 + (4 + 56*x + 182*x^2 + 126*x^3 + 21*x^4)*exp(x)). - _G. C. Greubel_, May 26 2023
%p A008385 1, seq((21*n^4 +35*n^2 +4)/2, n=1..50);
%t A008385 Table[n^2*(21*n^2 +35)/2 +2 -Boole[n==0], {n,0,50}] (* _G. C. Greubel_, May 26 2023 *)
%o A008385 (Maxima) A008385[n]:=21/2*n^4+35/2*n^2+2$
%o A008385 makelist(A008385[n],n,0,30); /* _Martin Ettl_, Oct 26 2012 */
%o A008385 (Magma) [n eq 0 select 1 else (21*n^4 +35*n^2 +4)/2: n in [0..50]]; // _G. C. Greubel_, May 26 2023
%o A008385 (SageMath) [n^2*(21*n^2 +35)/2 +2 -int(n==0) for n in range(51)] # _G. C. Greubel_, May 26 2023
%K A008385 nonn,easy
%O A008385 0,2
%A A008385 _N. J. A. Sloane_ and _J. H. Conway_