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 A010883 #43 Dec 30 2024 03:57:44
%S A010883 1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,
%T A010883 3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,
%U A010883 1,2,3,4,1,2,3,4,1,2,3,4,1
%N A010883 Simple periodic sequence: repeat 1,2,3,4.
%C A010883 Partial sums are given by A130482(n) + n + 1. - _Hieronymus Fischer_, Jun 08 2007
%C A010883 1234/9999 = 0.123412341234... - _Eric Desbiaux_, Nov 03 2008
%H A010883 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1).
%F A010883 a(n) = 1 + (n mod 4). - _Paolo P. Lava_, Nov 21 2006
%F A010883 From _Hieronymus Fischer_, Jun 08 2007: (Start)
%F A010883 a(n) = A010873(n) + 1.
%F A010883 Also a(n) = (1/2)*(5 - (-1)^n - 2*(-1)^((2*n - 1 + (-1)^n)/4)).
%F A010883 G.f.: g(x) = (4*x^3 + 3*x^2 + 2*x + 1)/(1 - x^4) = (4*x^5 - 5*x^4 + 1)/((1 - x^4)*(1-x)^2). (End)
%F A010883 a(n) = 5/2 - cos(Pi*n/2) - sin(Pi*n/2) - (-1)^n/2. - _R. J. Mathar_, Oct 08 2011
%t A010883 PadRight[{},120,{1,2,3,4}] (* _Harvey P. Dale_, Aug 02 2016 *)
%o A010883 (PARI) a(n)=(n-1)%4+1 \\ _Charles R Greathouse IV_, Jun 11 2015
%o A010883 (Python)
%o A010883 def A010883(n): return 1 + (n & 3) # _Chai Wah Wu_, May 25 2022
%Y A010883 Cf. A010872, A010873, A010874, A010875, A010876, A004526, A002264, A002265, A002266.
%Y A010883 Cf. A177037 (decimal expansion of (9+2*sqrt(39))/15). - _Klaus Brockhaus_, May 01 2010
%K A010883 nonn,easy
%O A010883 0,2
%A A010883 _N. J. A. Sloane_