where "A" depends on "a", "b", and "c" but not on "n". By the prime number theorem, this formula with "A" set equal to one is the asymptotic number of primes less than "n" expected in a random set of numbers having the same density as the set of numbers of the form "ax"2 + "bx" + "c". But since "A" can take values bigger or smaller than 1, some polynomials, according to the conjecture, will be especially rich in primes, and others especially poor. An unusually rich polynomial is 4"x"2 − 2"x" + 41 which forms a visible line in the Ulam spiral. The constant "A" for this polynomial is approximately 6.6, meaning that the numbers it generates are almost seven times as likely to be prime as random numbers of comparable size, according to the conjecture. This particular polynomial is related to Euler's prime-generating polynomial "x"2 − "x" + 41 by replacing "x" with 2"x", or equivalently, by restricting "x" to the even numbers. The constant "A" is given by a product running over all prime numbers,