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 A163989 #23 May 19 2025 13:11:12
%S A163989 1,26,8,200,26,620,56,1304,98,2252,152,3464,218,4940,296,6680,386,
%T A163989 8684,488,10952,602,13484,728,16280,866,19340,1016,22664,1178,26252,
%U A163989 1352,30104,1538,34220,1736,38600,1946,43244,2168,48152,2402,53324,2648,58760,2906
%N A163989 First differences of A160379.
%H A163989 Harvey P. Dale, <a href="/A163989/b163989.txt">Table of n, a(n) for n = 1..1000</a>
%H A163989 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A163989 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1).
%F A163989 a(2n+1) = 6n^2 + 2 for n>=1.
%F A163989 a(2n) = 132n^2 - 240n + 152 for n>=2.
%F A163989 From _Colin Barker_, Sep 17 2013: (Start)
%F A163989 a(n) = 3*a(n-2)-3*a(n-4)+a(n-6) for n>8.
%F A163989 G.f.: -x*(18*x^3+x^2+26*x+1)*(x^4+4*x^2+1) / ((x-1)^3*(x+1)^3). (End)
%t A163989 LinearRecurrence[{0,3,0,-3,0,1},{1,26,8,200,26,620,56,1304},50] (* _Harvey P. Dale_, May 19 2025 *)
%o A163989 (PARI) Vec(-x*(18*x^3+x^2+26*x+1)*(x^4+4*x^2+1)/((x-1)^3*(x+1)^3) + O(x^100)) \\ _Colin Barker_, Sep 17 2013
%Y A163989 Cf. A160117, A160119, A160379, A160428, A161340, A163987.
%K A163989 nonn,easy
%O A163989 1,2
%A A163989 _Omar E. Pol_, Sep 20 2009
%E A163989 Formula and more terms from _Nathaniel Johnston_, Nov 15 2010
%E A163989 More terms from _Colin Barker_, Sep 17 2013