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 A022149 #25 Sep 06 2023 01:36:08
%S A022149 1,98,1946,16394,83442,307314,907018,2282394,5095650,10368386,
%T A022149 19594106,34866218,59021522,95799186,150015210,227752378,336565698,
%U A022149 485703330,686343002,951843914,1298014130,1743393458
%N A022149 Coordination sequence for root lattice B_7.
%H A022149 Vincenzo Librandi, <a href="/A022149/b022149.txt">Table of n, a(n) for n = 0..1000</a>
%H A022149 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, Zeit. f. Kristallographie, 212 (1997), 253-256.
%H A022149 R. Bacher, P. de la Harpe and B. Venkov, <a href="http://dx.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 A022149 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1).
%F A022149 a(0) = 1; for n>0, a(n) = (968*n^6 - 1368*n^5 + 5420*n^4 - 4080*n^3 + 4232*n^2 - 852*n + 90)/45 . - _Philippe Deléham_, Feb 20 2004
%F A022149 G.f.: -(x^7+371*x^6+2793*x^5+6155*x^4+4795*x^3+1281*x^2+91*x+1)/(x-1)^7 = 1 +2*x*(x+1) *(49+581*x+1834*x^2+1226*^2+181*x^4+x^5) /(1-x)^7. - _Colin Barker_, Nov 18 2012
%t A022149 CoefficientList[Series[-(x^7 + 371 x^6 + 2793 x^5 + 6155 x^4 + 4795 x^3 + 1281 x^2 + 91 x + 1)/(x - 1)^7, {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 16 2013 *)
%t A022149 LinearRecurrence[{7,-21,35,-35,21,-7,1},{1,98,1946,16394,83442,307314,907018,2282394},30] (* _Harvey P. Dale_, Nov 20 2018 *)
%K A022149 nonn,easy
%O A022149 0,2
%A A022149 mbaake(AT)sunelc3.tphys.physik.uni-tuebingen.de (Michael Baake)