OFFSET
1,2
COMMENTS
The formula given simplifies to 2^(2*n*(n-1))-1. - Alexander M Kerr, Feb 10 2012
FORMULA
a(n) = Sum_{i=1..2*(n^2-n)} binomial(2*(n^2-n),i), n >= 1.
EXAMPLE
For n=1, a(1)=0 since a minimum of a 2 X 2 grid is required to have edges.
MATHEMATICA
Total[Table[Binomial[2(n^2-n), i], {i, 2(n^2-n)}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Alexander M Kerr, Jan 31 2010
STATUS
approved