| (-1)^n*a(n) is the determinant of the n X n matrix m_{i,j}=T(n+i,j) 1<=i,j<=n. where T(n,k) are the signed Stirling numbers of first kind A008275. Derived from methods given in Krattenthaler link. - Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 17 2005
Contribution from W. Edwin Clark (eclark(AT)math.usf.edu), Apr 09 2009: (Start)
a(n) is also the number of binary operations on an n element set which are
right (or left) cancellative. These are also called right (left) cancellative
magma or groupoids. The multiplication table of a right (left) cancellative
magma is an n by n matrix with entries from an n element set such that the
elements in each column (or row) are distinct. (End)
This sequence is mentioned in "Experimentation in Mathematics" as a sum-of-powers determinant. - John M. Campbell, May 7, 2011
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