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 A022145 #32 Sep 06 2023 01:34:12
%S A022145 1,18,74,170,306,482,698,954,1250,1586,1962,2378,2834,3330,3866,4442,
%T A022145 5058,5714,6410,7146,7922,8738,9594,10490,11426,12402,13418,14474,
%U A022145 15570,16706,17882,19098,20354,21650
%N A022145 Coordination sequence for root lattice B_3.
%C A022145 Also sequence found by reading the segment (1, 18) together with the line from 18, in the direction 18, 74,..., in the square spiral whose vertices are the generalized dodecagonal numbers A195162. - _Omar E. Pol_, Nov 02 2012
%H A022145 Vincenzo Librandi, <a href="/A022145/b022145.txt">Table of n, a(n) for n = 0..1000</a>
%H A022145 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 A022145 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 A022145 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3, -3, 1).
%F A022145 a(n) = 20*n^2-4*n+2, for n>0.
%F A022145 a(n) = 3*a(n-1)-3*a(n-2)+a(n-3) for n>3. G.f.: (1+15*x+23*x^2+x^3)/(1-x)^3. [_Colin Barker_, Apr 13 2012]
%t A022145 CoefficientList[Series[(1+15*x+23*x^2+x^3)/(1-x)^3,{x,0,40}],x] (* _Vincenzo Librandi_, Apr 20 2012 *)
%t A022145 Join[{1},LinearRecurrence[{3,-3,1},{18,74,170},40]] (* _Harvey P. Dale_, Dec 03 2012 *)
%o A022145 (Magma) [1] cat [20*n^2-4*n+2: n in [1..40]]; // _Vincenzo Librandi_, Apr 20 2012
%K A022145 nonn,easy
%O A022145 0,2
%A A022145 mbaake(AT)sunelc3.tphys.physik.uni-tuebingen.de (Michael Baake)