A.2 Permutations 307Sijji 123451 12 113 1314 17615 11525101Further values are given by Abramowitz and Stegun. Stirling numbers ap-
pear in Section 5.6.3 on distinct matrices with nondistinct determinants
and in Appendix A.6.
The matricessn(x) andSn(x) are defined as follows:sn(x)=[
sijxi−j]
n=
1
−x 12 x2
− 3 x 1− 6 x3
11 x2
− 6 x 124 x4
− 50 x3
35 x2
− 10 x 1............................... n,
Sn(x)=[
Sijxi−j]
n=
1
x 1x
2
3 x 1x
3
7 x
2
6 x 1x
4
15 x
3
25 x
2
10 x 1......................... n.
A.2 Permutations
Inversions, the Permutation Symbol
The firstnpositive integers 1, 2 , 3 ,...,n, can be arranged in a linear se-
quence inn! ways. For example, the first three integers can be arranged in
3! = 6 ways, namely
123
132
213
231
312
321
LetNndenote the set of the firstnintegers arranged in ascending order of
magnitude,
Nn={
123 ···n