A116542 Table B(m,n), read by antidiagonals, where B(m,n) is the number of ways integers 1,..,m*n can be put into an m X n grid so that every adjacent (NESW) pair of integers are coprime.

1, 2, 2, 6, 8, 6, 12, 16, 16, 12, 72, 432, 2016, 432, 72, 72, 2784, 23904, 23904, 2784, 72, 864, 35712, 7102656, 19611648, 7102656, 35712, 864

Offset: 1

Author

Giovanni Resta, Mar 28 2006

Keywords

• nonn
• tabl

Comments

Sequence suggested by Leroy Quet on the SeqFan mailing list. B(1,n)=B(n,1)=A076220(n).

Examples

			The 16 configuration 3x2 are the following
------------------------------------------------
1 2 3 | 2 5 6 | 3 4 1 | 4 5 6 | 6 1 2 | 6 5 4
6 5 4 | 3 4 1 | 2 5 6 | 3 2 1 | 5 4 3 | 1 2 3
------------------------------------------------
1 4 3 | 3 2 1 | 3 4 5 | 5 2 3 | 6 1 4
6 5 2 | 4 5 6 | 2 1 6 | 6 1 4 | 5 2 3
------------------------------------------------
2 1 6 | 3 2 5 | 4 1 6 | 5 4 3 | 6 5 2
3 4 5 | 4 1 6 | 3 2 5 | 6 1 2 | 1 4 3
------------------------------------------------
		

Crossrefs

Cf. A076220.