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A116542
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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.
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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
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Sequence suggested by Leroy Quet on the SeqFan mailing list. B(1,n)=B(n,1)=A076220(n).
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EXAMPLE
| The 16 configuration 3x2 are the following
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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
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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
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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
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CROSSREFS
| Cf. A076220.
Sequence in context: A101343 A134457 A092522 * A142243 A091441 A099490
Adjacent sequences: A116539 A116540 A116541 * A116543 A116544 A116545
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KEYWORD
| nonn,tabl
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AUTHOR
| Giovanni Resta (g.resta(AT)iit.cnr.it), Mar 28 2006
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