A270246 Array read by antidiagonals: T(n,m) = number of matchings (i.e., Hosoya index) in C_n X C_m.

1, 2, 2, 4, 7, 4, 7, 32, 32, 7, 11, 108, 370, 108, 11, 18, 342, 2764, 2764, 342, 18, 29, 1104, 19874, 41025, 19874, 1104, 29, 47, 3544, 144108, 576287, 576287, 144108, 3544, 47, 76, 11396, 1043060, 8205424, 15637256, 8205424, 1043060, 11396, 76

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..284

Eric Weisstein's World of Mathematics, Independent Edge Set

Eric Weisstein's World of Mathematics, Matching

Eric Weisstein's World of Mathematics, Torus Grid Graph

Formula

T(1, m) = A000032(m) for m<>2.

Example

The start of the sequence as table:
*   1    2      4       7        11          18 ...
*   2    7     32     108       342        1104 ...
*   4   32    370    2764     19874      144108 ...
*   7  108   2764   41025    576287     8205424 ...
*  11  342  19874  576287  15637256   430996378 ...
*  18 1104 144108 8205424 430996378 23079663560 ...
* ...

Crossrefs

Main diagonal is A270247. Row 2 is A102080.

Sequence in context: A210600 A220308 A203975 * A297889 A298294 A299388

Adjacent sequences: A270243 A270244 A270245 * A270247 A270248 A270249

Keyword

nonn,tabl

Author

Andrew Howroyd, Mar 13 2016

Status

approved