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 A050927 #19 Mar 16 2020 20:14:14
%S A050927 1,2,10,31,90,222,520,1090,2180,4090,7356,12660,21105,34020,53460,
%T A050927 81891,122826,180510,260746,370370,518518,715870,976170,1315470,
%U A050927 1753975,2314936,3027224,3923845,5044920,6436200,8152542,10255896
%N A050927 Number of directed multigraphs with loops on 3 nodes with n arcs.
%H A050927 Andrew Howroyd, <a href="/A050927/b050927.txt">Table of n, a(n) for n = 0..1000</a>
%H A050927 <a href="/index/Rec#order_19">Index entries for linear recurrences with constant coefficients</a>, signature (2,3,-5,-8,3,19,4,-24,-15,15,24,-4,-19,-3,8,5,-3,-2,1).
%F A050927 G.f.: (x^10+3*x^8+10*x^7+16*x^6+12*x^5+16*x^4+10*x^3+3*x^2+1) / ((1-x^3)^3*(1-x^2)^4*(1-x)^2).
%t A050927 <<Combinatorica`
%t A050927 nn=30;n=3;CoefficientList[Series[CycleIndex[Join[PairGroup[SymmetricGroup[n],Ordered],Permutations[Range[n*(n - 1) + 1, n*(n - 1) + n]], 2], s] /.Table[s[i] -> 1/(1 - x^i), {i, 1, n^2 - n}], {x, 0, nn}], x] (* _Geoffrey Critzer_, Aug 07 2015 *)
%t A050927 CoefficientList[Series[(x^10 + 3 x^8 + 10 x^7 + 16 x^6 + 12 x^5 + 16 x^4 + 10 x^3 + 3 x^2 + 1)/((1 - x^3)^3 (1 - x^2)^4 (1 - x)^2), {x, 0, 33}], x] (* _Vincenzo Librandi_, Aug 08 2015 *)
%o A050927 (PARI) Vec((1 + 3*x^2 + 10*x^3 + 16*x^4 + 12*x^5 + 16*x^6 + 10*x^7 + 3*x^8 + x^10)/((1 - x)^2*(1 - x^2)^4*(1 - x^3)^3) + O(x^40)) \\ _Andrew Howroyd_, Mar 16 2020
%Y A050927 Column k=3 of A138107.
%Y A050927 Cf. A005993.
%K A050927 easy,nonn
%O A050927 0,2
%A A050927 _Vladeta Jovovic_, Dec 30 1999