id:A108470 - OEIS Search Results

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Table read by antidiagonals: T(n,k) = number of labeled partitions of (n,k) into pairs (i,j).

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1, 1, 1, 1, 3, 1, 1, 7, 7, 1, 1, 15, 25, 15, 1, 1, 31, 79, 79, 31, 1, 1, 63, 241, 339, 241, 63, 1, 1, 127, 727, 1351, 1351, 727, 127, 1, 1, 255, 2185, 5235, 6721, 5235, 2185, 255, 1, 1, 511, 6559, 20119, 31831, 31831, 20119, 6559, 511, 1, 1, 1023, 19681, 77379 (list; table; graph; listen)

	OFFSET	`1,5`
	COMMENT	`Partitions of n black objects labeled 1..n and n white objects labeled 1..n. Each partition must have at least one black object and at least one white object`
	FORMULA	`Double e.g.f.: exp((exp(x)-1)*(exp(y)-1)).`
	EXAMPLE	`1 1 1 1 1 ...` `1 3 7 15 31 ...` `1 7 25 79 241 ...` `1 15 79 339 1351 ...` `1 31 241 1351 6721 ...`
	CROSSREFS	`Cf. A108461. Columns 1-3: A000012, A000225, A058481. Main diagonal: A023997.` `Sequence in context: A132733 A082039 A063394 this_sequence A136126 A046802 A022166` `Adjacent sequences: A108467 A108468 A108469 this_sequence A108471 A108472 A108473`
	KEYWORD	`nonn,tabl`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Jun 03 2005`

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Last modified September 6 09:40 EDT 2008. Contains 143480 sequences.

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