OFFSET
3,2
COMMENTS
This gives the number of matroid bases that contain a given element (edge) of the bicircular matroid of K_n.
REFERENCES
O. Giménez, A. de Mier, M. Noy, On the Number of Bases of Bicircular Matroids, Ann. Comb. 9 (2005), no. 1, 35-45.
FORMULA
a(n) = 2*b(n)/(n-1), where b(n) is seq A137916.
EXAMPLE
a(4)=10 means that 10 (of the 15) labeled unicyclic graphs on 4 vertices contain a given edge.
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary Gordon, Jan 25 2013
STATUS
approved