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 A256524 #13 Apr 26 2017 08:49:30
%S A256524 1,3,9,18,34,54,84,120,169,225,297,378,478,588,720,864,1033,1215,1425,
%T A256524 1650,1906,2178,2484,2808,3169,3549,3969,4410,4894,5400,5952,6528,
%U A256524 7153,7803,8505,9234,10018,10830,11700,12600,13561,14553,15609,16698,17854,19044
%N A256524 Number of partitions of 3n into at most 4 parts.
%H A256524 Colin Barker, <a href="/A256524/b256524.txt">Table of n, a(n) for n = 0..1000</a>
%H A256524 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-2,2,-2,0,2,-1).
%F A256524 G.f.: (x^2+x+1)*(2*x^2+1) / ((x-1)^4*(x+1)^2*(x^2+1)).
%F A256524 a(n) = A001400(3n). - _Alois P. Heinz_, Apr 01 2015
%e A256524 For n=1 the 3 partitions of 1*3 = 3 are [3], [1,2] and [1,1,1].
%t A256524 LinearRecurrence[{2, 0, -2, 2, -2, 0, 2, -1}, {1, 3, 9, 18, 34, 54, 84, 120}, 50] (* _Jean-François Alcover_, Apr 26 2017 *)
%o A256524 (PARI) concat(1, vector(40, n, k=0; forpart(p=3*n, k++, , [1,4]); k))
%o A256524 (PARI) Vec((x^2+x+1)*(2*x^2+1)/((x-1)^4*(x+1)^2*(x^2+1)) + O(x^100))
%Y A256524 Cf. A001400, A077043 (3 parts), A256525 (5 parts), A256315 (6 parts).
%K A256524 nonn,easy
%O A256524 0,2
%A A256524 _Colin Barker_, Apr 01 2015