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 A065530 #30 Dec 28 2024 19:34:36
%S A065530 0,1,8,3,24,5,48,7,80,9,120,11,168,13,224,15,288,17,360,19,440,21,528,
%T A065530 23,624,25,728,27,840,29,960,31,1088,33,1224,35,1368,37,1520,39,1680,
%U A065530 41,1848,43,2024,45,2208,47,2400,49,2600,51,2808,53,3024,55,3248,57
%N A065530 If n is odd then a(n) = n, else a(n) = n*(n+2).
%C A065530 Order of Fibonacci group F(n+1,2) (0 means group is infinite). - _N. J. A. Sloane_, Dec 30 2011
%D A065530 D. L. Johnson, Presentation of Groups, Cambridge, 1976, p. 182.
%D A065530 Thomas, Richard M., The Fibonacci groups revisited, in Groups - St. Andrews 1989, Vol. 2, 445-454, London Math. Soc. Lecture Note Ser., 160, Cambridge Univ. Press, Cambridge, 1991.
%H A065530 Harry J. Smith, <a href="/A065530/b065530.txt">Table of n, a(n) for n = 0..1000</a>
%H A065530 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1).
%F A065530 O.g.f.: (x+8x^2-x^5)/(1-x^2)^3. - _Len Smiley_, Dec 04 2001
%F A065530 a(n) = 3*a(n-2)-3*a(n-4)+a(n-6) for n>5. - _Colin Barker_, May 02 2015
%t A065530 Array[If[OddQ[#], #, #*(#+2)] &, 100, 0] (* _Paolo Xausa_, Feb 22 2024 *)
%t A065530 With[{nn=60},Riffle[Table[n(n+2),{n,0,nn,2}],Range[1,nn+1,2]]] (* or *) LinearRecurrence[{0,3,0,-3,0,1},{0,1,8,3,24,5},100] (* _Harvey P. Dale_, Sep 27 2024 *)
%o A065530 (PARI) a(n) = { if (n%2, n, n*(n + 2)) } \\ _Harry J. Smith_, Oct 20 2009
%o A065530 (PARI) concat(0, Vec(x*(x^4-8*x-1)/((x-1)^3*(x+1)^3) + O(x^100))) \\ _Colin Barker_, May 02 2015
%Y A065530 A column of A202624.
%K A065530 easy,nonn
%O A065530 0,3
%A A065530 _George E. Antoniou_, Dec 02 2001