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

1,7

Links

Andrew Howroyd, Table of n, a(n) for n = 1..78

Eric Weisstein's World of Mathematics, Graph Cycle, Rook Graph

Example

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 ...
  ...

Crossrefs

Main diagonal is A234624.

Columns 1..3 are A002807, A341500, A341501.

Cf. A269562, A269565.

Sequence in context: A225556 A064666 A269160 * A040042 A233366 A232831

Adjacent sequences: A286415 A286416 A286417 * A286419 A286420 A286421

Keyword

nonn,tabl

Author

Andrew Howroyd, May 08 2017

Status

approved