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 A036407 #17 Sep 08 2022 08:44:52
%S A036407 0,1,1,1,2,3,4,6,8,9,12,14,16,19,22,25,29,33,36,41,45,49,54,59,64,70,
%T A036407 76,81,88,94,100,107,114,121,129,137,144,153,161,169,178,187,196,206,
%U A036407 216,225,236,246,256,267,278,289,301,313,324,337,349
%N A036407 a(n) = ceiling(n^2/9).
%H A036407 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,0,0,0,0,1,-2,1).
%F A036407 From _R. J. Mathar_, Jan 22 2011: (Start)
%F A036407 a(n) = 2*a(n-1) - a(n-2) + a(n-9) - 2*a(n-10) + a(n-11).
%F A036407 G.f.: -x*(1+x)*(x^8 - 2*x^7 + 2*x^6 - x^5 + x^4 - x^3 + 2*x^2 - 2*x + 1) / ( (1+x+x^2)*(x^6+x^3+1)*(x-1)^3 ). (End)
%p A036407 A036407:=n->ceil(n^2/9): seq(A036407(n), n=0..100); # _Wesley Ivan Hurt_, Mar 10 2015
%t A036407 Table[Ceiling[n^2/9], {n, 0, 100}] (* _Wesley Ivan Hurt_, Mar 10 2015 *)
%t A036407 LinearRecurrence[{2,-1,0,0,0,0,0,0,1,-2,1},{0,1,1,1,2,3,4,6,8,9,12},60] (* _Harvey P. Dale_, Nov 02 2020 *)
%o A036407 (Magma) [Ceiling(n^2/9) : n in [0..100]]; // _Wesley Ivan Hurt_, Mar 10 2015
%K A036407 nonn,easy
%O A036407 0,5
%A A036407 _N. J. A. Sloane_