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 A121833 #23 Mar 15 2024 10:02:56
%S A121833 1,0,1,1,1,2,3,3,6,7,10,15,20,28,41,55,79,111,154,218,306,427,603,844,
%T A121833 1184,1665,2334,3276,4602,6454,9062,12721,17850,25059,35173,49363,
%U A121833 69294,97257,136507,191610,268937,377480,529841,743674,1043828,1465125
%N A121833 Expansion of 1/(1-x^2-x^3-x^6).
%C A121833 Number of compositions of n into parts 2, 3, and 6. [_Joerg Arndt_, Sep 03 2013]
%H A121833 Vincenzo Librandi, <a href="/A121833/b121833.txt">Table of n, a(n) for n = 0..1000</a>
%H A121833 S. Dominique Andres, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL14/Andres/andres3.html">On Multiperiodic Infinite Recursions and Their Finite Core</a>, J. Int. Seq. 14 (2011) # 11.2.7
%H A121833 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,1,0,0,1).
%F A121833 a(n) = a(n-2) + a(n-3) + a(n-6).
%F A121833 G.f.: -1 / ( (1+x)*(x^5-x^4+x^3+x-1) ). - _R. J. Mathar_, Aug 09 2017
%t A121833 CoefficientList[Series[1 / (1 - x^2 - x^3 - x^6), {x, 0, 50}], x] (* _Vincenzo Librandi_, Sep 03 2013 *)
%t A121833 LinearRecurrence[{0,1,1,0,0,1},{1,0,1,1,1,2},50] (* _Harvey P. Dale_, Dec 16 2016 *)
%o A121833 (Magma) I:=[1,0,1,1,1,2]; [n le 6 select I[n] else Self(n-2)+Self(n-3)+Self(n-6): n in [1..50]]; // _Vincenzo Librandi_, Sep 03 2013
%K A121833 easy,nonn
%O A121833 0,6
%A A121833 _Jon E. Schoenfield_, Aug 27 2006