A360877 Array read by antidiagonals: T(m,n) is the number of (undirected) paths in the rook graph K_m X K_n.

0, 1, 1, 6, 12, 6, 30, 129, 129, 30, 160, 1984, 4536, 1984, 160, 975, 45945, 310542, 310542, 45945, 975, 6846, 1524156, 38298270, 111933456, 38298270, 1524156, 6846

Offset

1,4

Links

Table of n, a(n) for n=1..28.

Eric Weisstein's World of Mathematics, Graph Path.

Eric Weisstein's World of Mathematics, Rook Graph.

Example

Array begins:
==============================================
m\n|   1     2        3         4        5 ...
---+------------------------------------------
1  |   0     1        6        30      160 ...
2  |   1    12      129      1984    45945 ...
3  |   6   129     4536    310542 38298270 ...
4  |  30  1984   310542 111933456 ...
5  | 160 45945 38298270 ...
  ...

Crossrefs

Main diagonal is A288967.

Rows 1..2 are A038155, A360878.

Cf. A269562, A269565, A286418, A360851, A360855.

Sequence in context: A050496 A262617 A303226 * A295122 A103698 A175375

Adjacent sequences: A360874 A360875 A360876 * A360878 A360879 A360880

Keyword

nonn,tabl,more

Author

Andrew Howroyd, Feb 25 2023

Status

approved