How do i create a java random number generator that creates 3 numbers using seeds?

I am trying to create a random number generator with java that and output 3 numbers from 1-8 using seeds from user input, such as a user imputting 1 as a seed it sets out a set of 3 numbers then sets out another 3 numbers, if the user inputs another seed such as 4 then it will give a different set of numbers? I know to use scnr.nextInt(); for the user input for the seed, but how do i use it for the seed and number generator?