Ex(A) = (A · Ex−1(A))/(x + A · Ex−1(A))
, E0(A) = 1
This recursion formula is exact, and even for large values of (n,A)
there are no round off errors. It is the basic formula for numerous tables of the Erlang B formula.
You must involve a cycle to evaluate needed number of servers(lines). The index in the bottom of E is the number of channels. It asumes that if there is no available cirquits, hence, all traffic will be lost.
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