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 A130848 #27 Dec 12 2023 09:41:22
%S A130848 2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,
%T A130848 -5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,
%U A130848 5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3,2,5,3,-2,-5,-3
%N A130848 Periodic sequence with period (2, 5, 3, -2, -5, -3).
%C A130848 Also binomial transform of periodic sequence with period (2, 3, -5).
%C A130848 Sequence is identical to its third differences.
%H A130848 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,-1).
%F A130848 For n > 1, a(n) = a(n-1) - a(n-2).
%F A130848 a(n) = a(n-6).
%F A130848 G.f.: (2+3*x)/(1-x+x^2).
%F A130848 a(n) = 2*cos(Pi*n/3) + (8/3)*3^(1/2)*sin(Pi*n/3). - _R. J. Mathar_, Nov 15 2007
%t A130848 LinearRecurrence[{1,-1},{2,5},120] (* or *) PadRight[{},120,{2,5,3,-2,-5,-3}] (* _Harvey P. Dale_, Dec 27 2022 *)
%o A130848 (PARI) {m=104; a=2; b=5; print1(a=2, ",", b=5, ","); for(n=2, m, print1(c=b-a, ","); a=b; b=c)} /* _Klaus Brockhaus_, Jul 30 2007 */
%o A130848 (Magma) m:=105; [ [2, 5, 3, -2, -5, -3][ (n-1) mod 6 + 1 ]: n in [1..m] ]; /* _Klaus Brockhaus_, Jul 30 2007 */
%K A130848 sign,easy
%O A130848 0,1
%A A130848 _Paul Curtz_, Jul 21 2007
%E A130848 Edited by _Klaus Brockhaus_, Jul 30 2007