

A212806


Number of n X n matrices in which each row is a permutation of [1..n] and which contain no column rises.


4



1, 3, 163, 271375, 21855093751, 128645361626874561, 78785944892341703819175577, 6795588328283070704898044776213094655, 107414633522643325764587104395687638119674465944431, 392471529081605251407320880492124164530148025908765037878553312273, 407934916447631403509359040563002566177814886353044858592046202746464825839911293037
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OFFSET

1,2


COMMENTS

A column rise in a matrix M=(m_{i,j}) is a value of j such that m_{i,j} < m_{i,j+1} for all i = 1..n


REFERENCES

Abramson, Morton; Promislow, David. Enumeration of arrays by column rises. J. Combinatorial Theory Ser. A 24 (1978), no. 2, 247250. MR0469773 (57 #9554). [their a(5) is wrong, see A212845]


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..18


FORMULA

Abramson and Promislow give a g.f. for R(m,n,t), the number of m X n matrices in which each row is a permutation of [1..n] and which contain exactly t column rises:
1 + Sum_{n=1..oo} Sum_{t=0..n1} R(m,n,t) y^t x^n/(n!)^m = (y1)/(yf(x(y1)))
where f(x) = Sum_{i=0..oo} x^i/(i!)^m.


EXAMPLE

For n=2 the three matrices are [12/21], [21/12], [21/21] (but not [12/12]).


CROSSREFS

A212805 is a lower bound. Cf. A212855.
Sequence in context: A157586 A042439 A212845 * A030258 A154737 A112896
Adjacent sequences: A212803 A212804 A212805 * A212807 A212808 A212809


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, May 27 2012


EXTENSIONS

Corrected by R. H. Hardin, May 28 2012


STATUS

approved



