A286912 Array read by antidiagonals: T(m,n) = number of edge covers in the grid graph P_m X P_n.

0, 1, 1, 1, 7, 1, 2, 43, 43, 2, 3, 277, 969, 277, 3, 5, 1777, 23663, 23663, 1777, 5, 8, 11407, 571099, 2180738, 571099, 11407, 8, 13, 73219, 13807469, 198906617, 198906617, 13807469, 73219, 13, 21, 469981, 333735575, 18169793971, 68534828391, 18169793971, 333735575, 469981, 21

Offset: 1

Author

Andrew Howroyd, May 15 2017

Keywords

• nonn
• tabl

Examples

			Table starts:
======================================================================
m\n| 1     2        3           4              5                 6
---|------------------------------------------------------------------
1  | 0     1        1           2              3                 5 ...
2  | 1     7       43         277           1777             11407 ...
3  | 1    43      969       23663         571099          13807469 ...
4  | 2   277    23663     2180738      198906617       18169793971 ...
5  | 3  1777   571099   198906617    68534828391    23650967140325 ...
6  | 5 11407 13807469 18169793971 23650967140325 30833670159649637 ...
...
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..276
• Eric Weisstein's World of Mathematics, Edge Cover
• Eric Weisstein's World of Mathematics, Grid Graph

Crossrefs

Rows 1-3 are A000045(n-1), A286911, A288031.

Main diagonal is A286913.

Cf. A210662, A099390, A089934, A218354.

Extensions

T(1,1) corrected by Andrew Howroyd, Jun 04 2017