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 A013983 #36 Jul 08 2025 02:51:43
%S A013983 1,0,1,1,2,3,5,7,12,18,29,45,71,111,175,274,431,676,1062,1667,2618,
%T A013983 4110,6454,10133,15911,24982,39226,61590,96706,151842,238415,374346,
%U A013983 587779,922899,1449088,2275281,3572527
%N A013983 Expansion of 1/(1-x^2-x^3-x^4-x^5-x^6).
%C A013983 Number of compositions of n into parts p where 2 <= p < = 6. [_Joerg Arndt_, Jun 24 2013]
%H A013983 Vincenzo Librandi, <a href="/A013983/b013983.txt">Table of n, a(n) for n = 0..1000</a>
%H A013983 R. Mullen, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL12/Mullen/mullen2.html">On Determining Paint by Numbers Puzzles with Nonunique Solutions</a>, JIS 12 (2009) 09.6.5.
%H A013983 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,1,1,1,1).
%F A013983 a(n) = a(n-6) + a(n-5) + a(n-4) + a(n-3) + a(n-2). - _Jon E. Schoenfield_, Aug 07 2006
%F A013983 G.f.: 1 / ( (1+x)*(1-x^5-x^3-x)). a(n)+a(n+1) = A060961(n). - _R. J. Mathar_, Mar 22 2011
%t A013983 CoefficientList[Series[1 / (1 - x^2 - x^3 - x^4 - x^5 - x^6), {x, 0, 50}], x] (* _Vincenzo Librandi_, Jun 23 2013 *)
%t A013983 LinearRecurrence[{0,1,1,1,1,1},{1,0,1,1,2,3},50] (* _Harvey P. Dale_, Dec 31 2013 *)
%o A013983 (PARI) Vec(1/(1-x^2-x^3-x^4-x^5-x^6)+O(x^99)) \\ _Charles R Greathouse IV_, Sep 26 2012
%o A013983 (Magma) m:=40; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-x^2-x^3-x^4-x^5-x^6))); // _Vincenzo Librandi_, Jun 24 2013
%Y A013983 First differences of A023437.
%K A013983 nonn,easy
%O A013983 0,5
%A A013983 _N. J. A. Sloane_