Simon.js

function simon(n = 4, start = 0) {
  if (n < 0) {
    throw new Error('1st input number is too low')
  }
  if (start < 0) {
    throw new Error('2nd input number is too low')
  }

  const colors  = [
    'red',
    'orange',
    'yellow',
    'green',
    'blue',
    'violet',
  ].sort(() => Math.random() - 0.5);

  if (n > colors.length) {
    throw new Error('1st input number is too high')
  }

  const seed = [
    0, 1, 2, 3, 4, 5, 6,
    1, 2, 3, 4, 5, 6, 0,
    2, 3, 4, 5, 6, 0, 1,
    3, 4, 5, 6, 0, 1, 2,
    5, 6, 0, 1, 2, 3, 4,
    4, 5, 6, 0, 1, 2, 3,
    6, 0, 1, 2, 3, 4, 5,
    0, 2, 1, 4, 3, 6, 5,
    1, 3, 2, 5, 4, 6, 0,
    2, 4, 3, 6, 5, 0, 1,
    3, 5, 4, 6, 1, 0, 2,
    4, 6, 5, 0, 2, 1, 3,
    5, 6, 1, 0, 3, 2, 4,
    6, 0, 2, 1, 4, 3, 5,
  ]

  if (start >= seed.length) {
    throw new Error('2nd input number is too high')
  }

  const serie = []
  const frequency = {}
  const marginOfError = 1 / n

  const cursors = {
    color: start,
    compensation: 0,
  }

  function getIndex(key) {
    const index = seed[cursors[key]] % n

    cursors[key] += index + n

    if (cursors[key] >= seed.length) {
      cursors[key] -= seed.length
    }

    return index
  }

  for (let i = 0; i < n; i++) {
    frequency[colors[i]] = 0
  }

  return () => {
    let color = colors[getIndex('color')]

    if (getIndex('compensation') % 2 === 0) {
      let pickAgain = true

      while (pickAgain) {
        if (frequency[color] <= marginOfError * serie.length) {
          pickAgain = false
        }
        else {
          color = colors[getIndex('color')]
        }
      }
    }

    frequency[color] += 1

    serie.push(color)

    return serie
  }
}

simon.rules = [
  'Inputs: 0-6, 0-98',
]

// for (let n = 2; n < 7; n++) {
//   console.log('___')
//   console.log(n)

//   const generator = simon(n)

//   let serie = generator()

//   for (let i = 0; i < 1024; i++) {
//     serie = generator()
//   }

//   let frequency = {}

//   serie.forEach(color => {
//     frequency[color] = (frequency[color] || 0) + 1
//   })


//   console.log(serie.slice(0, 12))
//   Object.keys(frequency).forEach(color => {
//     frequency[color] /= serie.length

//     console.log(color, `${(frequency[color] * 100).toFixed(2)}%`)
//   })
// }