A286418 Array read by antidiagonals: T(n,m) is the number of (undirected) cycles in the rook graph K_n X K_m.
0, 0, 0, 1, 1, 1, 7, 14, 14, 7, 37, 170, 312, 170, 37, 197, 2904, 13945, 13945, 2904, 197, 1172, 74779, 1241696, 3228524, 1241696, 74779, 1172, 8018, 2751790, 196846257, 1723178763, 1723178763, 196846257, 2751790, 8018
Offset: 1
Examples
Table starts: ================================================ m\n 1 2 3 4 5 --+--------------------------------------------- 1 | 0 0 1 7 37 ... 2 | 0 1 14 170 2904 ... 3 | 1 14 312 13945 1241696 ... 4 | 7 170 13945 3228524 1723178763 ... 5 | 37 2904 1241696 1723178763 6198979538330 ... ...
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..78
- Eric Weisstein's World of Mathematics, Graph Cycle, Rook Graph