I have an interesting problem with the combination and I'm a little stuck
Allows you to define a function p (xn) that returns the number '()' for the equation x Now x can only be in the form x1 + x2 + x3 ... xn This function is defined for n> = 2
Examples:
P (x2) = (x1 + x2) = 1
p (x3) = ((x1 + x2) + x3) and (x1 + (x2 + x3))
p (x4) =
((x1 + x2) + (x3 + x4))
(((x1 + x2) + x3) + x4)
((x1 + (x2 + x3)) + x4)
(x1 + ((x2 + x3) + x4))
(x1 + (x2 + (x3 + x4)))
etc. The remark (x1 + (x2 + x3) + x4) is not a valid example for each +
P, , , . , , ?
, , - x 1 - x n. P (n).
n-1 node. k- . k , P (k). n-k , P (n-k) . , P (k) P (n-k) .
k 1 n-1, , n :
P(n) = P(1)P(n-1) + P(2)P(n-2) + ··· + P(n-2)P(2) + P(n-1)P(1)
@DSM , . , . . :
P(n) = C(2n,n)/(n+1) where C(n,k) = n! / (k!(n-k)!)