Spectral Test in R

I would like to change my code in a way that 10000 points are placed in a [0,1]^2 plot. I tries changing 256 to 10000 but it generates weird placement. I should change the factors 137 and 187 but not sure how to change it. Anyone knows the logic behind?

Working sample:

nSim = 256
X=rep(0,nSim)
for (i in 2:nSim){
    X[i] = (137*X[i-1]+187)%%256 
}
plot(X[-1],X[-nSim],col="blue",type="p",pch="x",lwd=2)

My code:

nSim = 10000
X=rep(0,nSim)
for (i in 2:nSim){
  X[i] = ((137*X[i-1]+187)%%nSim)
}
plot(X[-1]/nSim,X[-nSim]/nSim,col="blue", type="p",pch=20,lwd=2)