Frank Drake is a neighbor of mine. Very fine man. He's taken up square dancing of late.
N = R* fp ne fl fi fc L
Where R* =The rate of formation of stars suitable for the development of intelligent life. Likewise, L (The length of time such civilizations release detectable signals into space.) is a whole number, not a fraction (fL) as Crichton suggests.
I'm not trying to be an upstart but it seems that the way Crichton writes the equation,
(N=N*fp ne fl fi fc fL)
well, it doesn't make sense.