login
Number of labeled pure 2-complexes on n nodes (0-simplexes) with 5 2-simplexes and 13 1-simplexes.
2

%I #5 May 10 2013 12:44:27

%S 540,65625,1272320

%N Number of labeled pure 2-complexes on n nodes (0-simplexes) with 5 2-simplexes and 13 1-simplexes.

%C 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=5,l=13.

%D 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.

%F a(n)=540*C(n, 6)+61845*C(n, 7)+762440*C(n, 8)+...

%Y Cf. A054557.

%K more,nonn,bref

%O 6,1

%A _Vladeta Jovovic_, Apr 10 2000