#include "isprime.bas"

Function PrimalityPretest(k As Integer) As Boolean
    Dim As Integer ppp(1 To 8) = {3,5,7,11,13,17,19,23}
    For i As Integer = 1 To Ubound(ppp)
        If k Mod ppp(i) = 0 Then Return (k <= 23)
    Next i
    Return True
End Function

Function isChernick(n As Integer, m As Integer) As Boolean
    Dim As Integer i, t = 9 * m

    If Not PrimalityPretest(6 * m + 1) Then Return False
    If Not PrimalityPretest(12 * m + 1) Then Return False

    For i = 1 To n-1
        If Not PrimalityPretest(t * (2 ^ i) + 1) Then Return False
    Next i

    If Not isPrime(6 * m + 1) Then Return False
    If Not isPrime(12 * m + 1) Then Return False

    For i = 1 To n - 2
        If Not isPrime(t * (2 ^ i) + 1) Then Return False
    Next i
    Return True
End Function

Dim As Uinteger multiplier, k, m = 1
For n As Integer = 3 To 9
    multiplier = Iif (n > 4, 2 ^ (n-4), 1)
    If n > 5 Then multiplier *= 5

    k = 1
    Do
        m = k * multiplier
        If isChernick(n, m) Then
            Print "a(" & n & ") has m = " & m
            Exit Do
        End If
        k += 1
    Loop
Next n
Sleep