We prove some connections between the growth of a function and its Mellin transform and apply these to study an explicit example in the theory of Beurling primes. The example has its generalised Chebyshev function given by [x]-1, and associated zeta function ζ₀(s) given via
$- (ζ'₀(s))/(ζ₀(s)) = ζ(s) - 1$,
where ζ is Riemann's zeta function. We study the behaviour of the corresponding Beurling integer counting function N(x), producing O- and Ω- results for the 'error' term. These are strongly influenced by the size of ζ(s) near the line Re s=1.