"""
https://en.wikipedia.org/wiki/Primality_test
This one has lesser tests or usage of % operator.
An alternative using primality mod 30 = 2 * 3 * 5 instead of 6 = 2 * 3 
"""
def prime_checker(n):
    if n in [2, 3, 5]:
        return True
    elif n % 2 == 0 or n % 3 == 0 or n % 5 == 0:
        return False
    
    a = int(n ** 0.5 / 30)
    b = [7, 11, 13, 17, 19, 23, 29, 31]
    
    for i in [30 * j for j in range(a + 1)]:
        if True in [n % (i + q) == 0 for q in b if i + q is not n]:
            return False
    return True 

// Actually worse than the original solution involving so much mathematics 
// but it can give you the nth group if you seek just that. 

const groupCombinations = (
  arr2D,
  len = arr2D.length,
  mapToLengths = e => e.length,
  lenArr1D = Array.from(arr2D, mapToLengths),
  reduceToProduct = (acc, cV) => [acc[0] * cV].concat(acc),
  lenProducts = lenArr1D.reduceRight(reduceToProduct, [1]),
  mapToGroupElement = (i) => (__, _i) => arr2D[_i][((~~(i / lenProducts[_i + 1]) % lenArr1D[_i]))],
  mapToGroup = (_, i) => Array.from({length: len}, mapToGroupElement(i))
) => [lenProducts[0], Array.from({length: lenProducts[0]}, mapToGroup)];

// Actually worse than the original solution involving so much mathematics 
// but it can give you the nth group if you seek just that. 

const groupCombinations = (
  arr2D,
  len = arr2D.length,
  mapToLengths = e => e.length,
  lenArr1D = Array.from(arr2D, mapToLengths),
  reduceToProduct = (acc, cV) => [acc[0] * cV].concat(acc),
  lenProducts = lenArr1D.reduceRight(reduceToProduct, [1]),
  mapToGroupElement = (i) => (__, _i) => arr2D[_i][((~~(i / lenProducts[_i + 1]) % lenProducts[_i]))],
  mapToGroup = (_, i) => Array.from({length: len}, mapToGroupElement(i))
) => [lenProducts[0], Array.from({length: lenProducts[0]}, mapToGroup)];

const revstr = (
  str,
  reduceToRevString = (acc, cV) => cV + acc,
  resStr = [...str].reduce(reduceToRevString, '')
) => resStr;

"""
https://en.wikipedia.org/wiki/Primality_test
This one has lesser tests or usage of % operator.
An alternative using primality mod 30 = 2 * 3 * 5 instead of 6 = 2 * 3 
"""
def prime_checker(n):
    if n in [2, 3, 5]:
        return True
    elif n % 2 == 0 or n % 3 == 0 or n % 5 == 0:
        return False
    
    a = int(n ** 0.5 / 30)
    b = [7, 11, 13, 17, 19, 23, 29, 31]
    
    for i in [30 * j for j in range(a)]:
        if True in [n % (i + q) == 0 for q in b]:
            return False
    return True

"""
https://en.wikipedia.org/wiki/Primality_test
This one has lesser tests or usage of % operator
"""
def prime_checker(n):
    if n in [2, 3, 5, 7]:
        return True
    elif n % 2 == 0 or n % 3 == 0:
        return False
    
    a = int(n ** 0.5 / 6)
    
    for i in [5 + 6 * j for j in range(a)]:
        if n % i == 0 or n % (i + 2) == 0:
            return False
    return True