Shuffle number from 0 to Input

Hi! I'll try to write it as simple as I can: how can I create a node, that would take a number as an input, and based on that, give me shuffled outputs? I know the basics of how nodes work and how to add outputs and hide them, but...

I'm trying to create a "randomizer" to my shape indices. I tried to create a pixel processor 1 x 16(maximum number of shapes), randomize it from 0 to input, but I can't wrap my head around how can I tell processor to look at each pixel and not pick a number that already in a row. I hope that anyone gets what I'm trying to say, thanks in advance!