A270246 Array read by antidiagonals: T(n,m) is the number of matchings in the torus grid graph 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
Examples
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 ... * ...
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.