SOLUTION: n>k+s+2 . How many permutations has the set {1,2,3...n} ,with condition that in the middle of the numbers 1 and 2 ( and 2 and 1) are exactly k numbers and in the middle of the numb

Algebra ->  Permutations -> SOLUTION: n>k+s+2 . How many permutations has the set {1,2,3...n} ,with condition that in the middle of the numbers 1 and 2 ( and 2 and 1) are exactly k numbers and in the middle of the numb      Log On


   

Question 1099427: n>k+s+2 . How many permutations has the set {1,2,3...n} ,with condition that in the middle of the numbers 1 and 2 ( and 2 and 1) are exactly k numbers and in the middle of the numbers 2 and 3 (and 3 and 2 ) are exactly (k+1) numbers?
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
What does "the middle of the numbers 1 and 2" and 
"the middle of the numbers 2 and 3" mean?  I've only heard
"middle of numbers" referring to their arithmetic average or mean.
Surely you don't mean the average of 1 and 2, which is 1.5, and
the average of 2 and 3, which is 2.5.  That wouldn't make any sense.
Please tell us what you're talking about.  You can use the message 
form below.
Edwin