Calculating Anti-Primes

[david_uwi]

Code: (Select All)

DefLng A-S
Dim p(20), k(250) As Integer
p(1) = 2: p(2) = 3: p(3) = 5: p(4) = 7: p(5) = 11: p(6) = 13: p(7) = 17: p(8) = 19: p(9) = 23: p(10) = 29
'yes these are primes
tt = Timer
Print "anti-prime, number of factors"
For i = 6 To 7000000 Step 2
    iq = i
    For j = 1 To 10
        k(j) = 0
        If p(j) > iq Then Exit For
        If iq = 1 Then Exit For
        Do Until (iq Mod p(j) <> 0)
            k(j) = k(j) + 1: iq = iq \ p(j)
        Loop
    Next j
    isum = 1
    For jk = 1 To j
        isum = (k(jk) + 1) * isum
    Next jk
    If isum > kmax Then
        Print i, isum
        kmax = isum
        knum = knum + 1
    End If
    k = 0
Next i
Print Timer - tt
Print knum + 3 'missed 1,2,4

Anti-primes have lots of small prime factors. So with that knowledge you can speed it up (a little)