Why my ar.ols does not have coefficients?

Question

phi1<-0.2
u<-1
x1<-c()
x1[1]<-u/(1-phi1)
for(i in 2:100)
{
    x1[i]<-u+phi1*x1[i-1]+rnorm(1,0,1)
}
ar.ols(x1,order.max=1,demean=F,intercept=T)