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 A008356 #23 Aug 20 2025 00:29:14
%S A008356 1,41,411,2051,6981,18733,42783,86983,161993,281713,463715,729675,
%T A008356 1105805,1623285,2318695,3234447,4419217,5928377,7824427,10177427,
%U A008356 13065429,16574909,20801199,25848919,31832409,38876161,47115251,56695771,67775261,80523141,95121143
%N A008356 Crystal ball sequence for D_5 lattice.
%H A008356 T. D. Noe, <a href="/A008356/b008356.txt">Table of n, a(n) for n = 0..1000</a>
%H A008356 <a href="/index/Cor#crystal_ball">Index entries for crystal ball sequences</a>
%H A008356 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 A008356 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,20,-15,6,-1).
%F A008356 G.f.: (1+x)*(1+34*x+146*x^2+34*x^3+x^4)/(1-x)^6. - _Colin Barker_, Mar 16 2012
%p A008356 18/5*n^5+9*n^4+38/3*n^3+10*n^2+71/15*n+1;
%t A008356 CoefficientList[Series[(1+x)*(1+34*x+146*x^2+34*x^3+x^4)/(1-x)^6,{x,0,30}],x] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{1,41,411,2051,6981,18733},30] (* _Harvey P. Dale_, Sep 03 2016 *)
%K A008356 nonn,easy
%O A008356 0,2
%A A008356 _N. J. A. Sloane_ and _J. H. Conway_