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 A282848 #17 Dec 22 2023 12:02:27
%S A282848 4,7,10,9,12,15,18,17,20,23,26,25,28,31,34,33,36,39,42,41,44,47,50,49,
%T A282848 52,55,58,57,60,63,66,65,68,71,74,73,76,79,82,81,84,87,90,89,92,95,98,
%U A282848 97,100,103,106,105,108,111,114,113,116,119,122,121,124,127
%N A282848 a(n) = 2*n + 1 + n mod 4.
%H A282848 Colin Barker, <a href="/A282848/b282848.txt">Table of n, a(n) for n = 1..1000</a>
%H A282848 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1).
%F A282848 For n > 4 a(n) = a(n - 4) + 8.
%F A282848 G.f.: x*(4 + 3*x + 3*x^2 - x^3 - x^4) / ((1 - x)^2*(1 + x)*(1 + x^2)). - _Colin Barker_, Feb 23 2017
%t A282848 Table[2*k + 1 + Mod[k, 4], {k, 100}]
%t A282848 CoefficientList[ Series[(4 + 3 x + 3 x^2 - x^3 - x^4)/((x -1)^2 (1 + x + x^2 + x^3)), {x, 0, 60}], x] (* or *)
%t A282848 LinearRecurrence[{1, 0, 0, 1, -1}, {4, 7, 10, 9, 12}, 70] (* _Robert G. Wilson v_, Feb 23 2017 *)
%o A282848 (PARI) Vec(x*(4 + 3*x + 3*x^2 - x^3 - x^4) / ((1 - x)^2*(1 + x)*(1 + x^2)) + O(x^100)) \\ _Colin Barker_, Feb 23 2017
%Y A282848 Cf. A143097, A083220.
%K A282848 nonn,easy
%O A282848 1,1
%A A282848 _Zak Seidov_, Feb 23 2017