Lind and Boyd conjectured that  the  smallest Perron number of degree n is a root of a trinomial with  coefficients 1, -1.  We investigate some properties of these trinomials,  such as number of roots which are greater than one in modulus and Mahler measure. We determine the limit of the rate $\frac{\nu}{n}$ between the number $\nu$ of roots of the trinomial $x^n-x^m-1$, $0<m<n$, which are greater than 1 in modulus, and degree $n$. The product of these $\nu$ roots has also a limit when $n\to\infty$. The explicit expression of the limit by an integral is presented. The computing of the rate and the product for $n=100,150$ as well as of its limits is presented.