OFFSET
1,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..15
N. Calkin, C. Merino, S. Noble and M. Noy, Improved Bounds for the Number of Forests and Acyclic Orientations in the Square Lattice, The Electronic Journal of Combinatorics, Volume 10(1), 2003, #R4.
A. Pönitz, Über eine Methode zur Konstruktion von Algorithmen für die Berechnung von Invarianten in endlichen ungerichteten Hypergraphen, PhD Thesis (2004) C.3.
Peter Tittmann, More Results [Gives a(1)-a(14)]
Eric Weisstein's World of Mathematics, Grid Graph
CROSSREFS
KEYWORD
nonn
AUTHOR
Andre Poenitz [André Pönitz], Peter Tittmann, Mar 03 2003
EXTENSIONS
Terms a(10) and beyond from Andrew Howroyd, Feb 22 2023
STATUS
approved