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 A276276 #19 Sep 10 2016 10:37:37
%S A276276 2,1,0,3,1,3,4,4,7,8,11,15,19,26,34,45,60,79,105,139,184,244,323,428,
%T A276276 567,751,995,1318,1746,2313,3064,4059,5377,7123,9436,12500,16559,
%U A276276 21936,29059,38495,50995,67554,89490
%N A276276 a(n) = a(n-2)+a(n-3) with a(1)=2 a(2)=1 a(3)=0.
%C A276276 Sequence is obtained from modulo 3 periodic sequence of Padovan numbers 1112201210010, it satisfies the same recurrence a(n) = a(n-2) + a(n-3).
%H A276276 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,1).
%F A276276 G.f.: (2x^2-x-2)/(x^3+x^2-1).
%F A276276 a(n) = A000931(n) - A000931(n-9), for n>2.
%t A276276 RecurrenceTable[{a[n] == a[n - 2] + a[n - 3], a[1] == 2, a[2] == 1, a[3] == 0}, a, {n, 1, 43}] (* or *)
%t A276276 CoefficientList[Series[(2 x^2 - x - 2)/(x^3 + x^2 - 1), {x, 0, 42}], x] (* _Michael De Vlieger_, Aug 28 2016 *)
%o A276276 (PARI) a(n)=([0,1,0; 0,0,1; 1,1,0]^(n-1)*[2;1;0])[1,1] \\ _Charles R Greathouse IV_, Aug 28 2016
%Y A276276 Cf. A000931, A060006.
%K A276276 nonn,easy
%O A276276 1,1
%A A276276 _Nicolas Bègue_, Aug 26 2016
%E A276276 More terms from _Charles R Greathouse IV_, Aug 28 2016