OFFSET
0,3
COMMENTS
The n X n matrix M is a Vandermonde matrix of (x, 2x, 3x, ..., j*x, ..., n*x) scaled by factorials. The first n coefficients of x in det(I - M) are always the same.
LINKS
Andrew J. Robbins, Table of n, a(n) for n = 0..50
FORMULA
E.g.f.: det(I - M) where M_jk = (j*x)^k/k!.
MATHEMATICA
A[n_] := D[Det[Table[KroneckerDelta[j, k] - (j*x)^k/k!, {j, 1, n}, {k, 1, n}]], {x, n}]/.x->0
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Andrew J. Robbins, Mar 02 2009
STATUS
approved