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A286912 Array read by antidiagonals: T(m,n) = number of edge covers in the grid graph P_m X P_n. 8
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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

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

EXAMPLE

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 ...

...

CROSSREFS

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

Main diagonal is A286913.

Cf. A210662, A099390, A089934, A218354.

Sequence in context: A317733 A258335 A266985 * A239807 A130875 A200923

Adjacent sequences:  A286909 A286910 A286911 * A286913 A286914 A286915

KEYWORD

nonn,tabl

AUTHOR

Andrew Howroyd, May 15 2017

EXTENSIONS

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

STATUS

approved

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Last modified June 21 03:51 EDT 2021. Contains 345354 sequences. (Running on oeis4.)