set = [1, 2, 3, 4, 5, 6]
picked = 0
Function PickNext(set, picked)
  If picked > Len(set) - 1 Then
    Return Nothing
  End If
  // random number between picked (inclusive) and length (exclusive)
  r = RandomInt(picked, Len(set))
  // swap the picked element to the beginning of the set
  result = set[r]
  set[r] = set[picked]
  set[picked] = result
  // update picked
  picked++
  // return your next random element
  Return temp
End Function

var set = [];
set.picked = 0;
function pickNext(set) {
    if(set.picked > set.length - 1) { return null; }
    var r = set.picked + Math.floor(Math.random() * (set.length - set.picked));
    var result = set[r];
    set[r] = set[set.picked];
    set[set.picked] = result;
    set.picked++;
    return result;
}

// testing
for(var i=0; i<100; i++) {
    set.push(i);
}
while(pickNext(set) !== null) { }
document.body.innerHTML += set.toString();

// on the fly set generator
var count = 0;
var maxValue = 64;
function nextElement() {
    // restart the generation
    if(count == maxValue) {
        count = 0;
    }
    return count++;
}

// code to pseudo randomly select elements
var current = 0;
var stack = [0, maxValue - 1];
function randomBinaryWalk() {
    if(stack.length == 0) { return null; }
    var high = stack.pop();
    var low = stack.pop();
    var mid = ((high + low) / 2) | 0;
    // pseudo randomly choose the next path
    if(Math.random() > 0.5) {
        if(low <= mid - 1) {
            stack.push(low);
            stack.push(mid - 1);
        }
        if(mid + 1 <= high) {
            stack.push(mid + 1);
            stack.push(high);
        }
    } else {
        if(mid + 1 <= high) {
            stack.push(mid + 1);
            stack.push(high);
        }
        if(low <= mid - 1) {
            stack.push(low);
            stack.push(mid - 1);
        }
    }
    // how many elements to skip
    var toMid = (current < mid ? mid - current : (maxValue - current) + mid);
    // skip elements
    for(var i = 0; i < toMid - 1; i++) {
        nextElement();
    }
    current = mid;
    // get result
    return nextElement();
}

// test
var result;
var list = [];
do {
    result = randomBinaryWalk();
    list.push(result);
} while(result !== null);
document.body.innerHTML += '<br/>' + list.toString();

package main

import (
    "fmt"
    "github.com/bwesterb/powercycle"
)

func main() {
    var x uint64
    cycle := powercycle.New(10)
    for i := 0; i < 10; i++ {
        fmt.Println(x)
        x = cycle.Apply(x)
    }
}

0
6
4
1
2
9
3
5
8
7

BenchmarkNew10-8                     1000000          1328 ns/op
BenchmarkNew1000-8                    500000          2566 ns/op
BenchmarkNew1000000-8                  50000         25893 ns/op
BenchmarkNew1000000000-8              200000          7589 ns/op
BenchmarkNew1000000000000-8             2000        648785 ns/op
BenchmarkApply10-8                  10000000           170 ns/op
BenchmarkApply1000-8                10000000           173 ns/op
BenchmarkApply1000000-8             10000000           172 ns/op
BenchmarkApply1000000000-8          10000000           169 ns/op
BenchmarkApply1000000000000-8       10000000           201 ns/op
BenchmarkApply1000000000000000-8    10000000           204 ns/op