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 A054648 #12 Jul 02 2025 16:01:59
%S A054648 360,13230,137760,835380,3679200,13056120,39584160,106383420,
%T A054648 259819560,586936350,1242521280,2489618040,4758324480,8728907040,
%U A054648 15446635200,26477304840,44114190120,71649152190,113722852320,176771479500,269590120800,404035889400,595897192800
%N A054648 Number of labeled pure 2-complexes on n nodes (0-simplexes) with 4 2-simplexes and 11 1-simplexes.
%C A054648 Number of {T_1,T_2,...,T_k} where T_i,i=1..k are 3-subsets of an n-set such that {D | D is 2-subset of T_i for some i=1..k} has l elements; k=4,l=11.
%D A054648 V. Jovovic, On the number of two-dimensional simplicial complexes (in Russian), Metody i sistemy tekhnicheskoy diagnostiki, Vypusk 16, Mezhvuzovskiy zbornik nauchnykh trudov, Izdatelstvo Saratovskogo universiteta, 1991.
%H A054648 T. D. Noe, <a href="/A054648/b054648.txt">Table of n, a(n) for n = 6..1000</a>
%F A054648 a(n) = 360*C(n, 6)+10710*C(n, 7)+42000*C(n, 8)+41580*C(n, 9)+12600*C(n, 10) = n*(n-1)*(n-2)*(n-3)*(n-4)*(n-5)*(n^4+3*n^3-58*n^2-120*n+1008)/288.
%F A054648 Empirical G.f.: -30*x^6*(89*x^4-391*x^3+401*x^2+309*x+12)/(x-1)^11. [_Colin Barker_, Jun 22 2012]
%Y A054648 Cf. A054557-A054562.
%K A054648 nonn
%O A054648 6,1
%A A054648 _Vladeta Jovovic_, Apr 16 2000
%E A054648 More terms from _James Sellers_, Apr 16 2000