OFFSET
6,1
COMMENTS
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=12.
REFERENCES
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.
FORMULA
a(n)=2700*C(n, 6)+99120*C(n, 7)+351960*C(n, 8)+...
CROSSREFS
KEYWORD
more,nonn,bref
AUTHOR
Vladeta Jovovic, Apr 10 2000
STATUS
approved