DefDbl A-Z
Dim crlf$
Private Sub Form_Load()
Text1.Text = ""
crlf$ = Chr(13) + Chr(10)
Form1.Visible = True
For n = 12345 To 98765
ns$ = LTrim(Str(n))
good = 1
For i = 1 To 4
If InStr(Mid(ns$, i + 1), Mid(ns$, i, 1)) > 0 Then good = 0
Next
If good Then
pf = n
While prmdiv(pf) > 1 And prmdiv(pf) < pf
pf = pf / prmdiv(pf)
Wend
If pf > 99 And pf < 1000 Then
pfs$ = LTrim(Str(pf))
If Mid(pfs$, 2, 1) = Mid(ns$, 1, 1) And Mid(pfs$, 3, 1) = Mid(ns$, 3, 1) Then
If InStr(ns$, Mid(pfs$, 1, 1)) = 0 Then
Text1.Text = Text1.Text & Str(pf) & Str(n) & " "
n2 = n
p = prmdiv(n2): n2 = n2 / p
While p > 1
Text1.Text = Text1.Text & Str(p)
p = prmdiv(n2): n2 = n2 / p
Wend
Text1.Text = Text1.Text & crlf
End If
End If
End If
End If
Next n
Text1.Text = Text1.Text & "----------------" & crlf
' the following is for a similar puzzle: WHY is smallest prime factor of HAYDN.
For n = 12345 To 98765
ns$ = LTrim(Str(n))
good = 1
For i = 1 To 4
If InStr(Mid(ns$, i + 1), Mid(ns$, i, 1)) > 0 Then good = 0
Next
If good Then
pf = prmdiv(n)
If pf > 99 And pf < 1000 Then
pfs$ = LTrim(Str(pf))
If Mid(pfs$, 2, 1) = Mid(ns$, 1, 1) And Mid(pfs$, 3, 1) = Mid(ns$, 3, 1) Then
If InStr(ns$, Mid(pfs$, 1, 1)) = 0 Then
Text1.Text = Text1.Text & Str(pf) & Str(n) & " "
n2 = n
p = prmdiv(n2): n2 = n2 / p
While p > 1
Text1.Text = Text1.Text & Str(p)
p = prmdiv(n2): n2 = n2 / p
Wend
Text1.Text = Text1.Text & crlf
End If
End If
End If
End If
Next n
End Sub
Function prmdiv(num)
Dim n, dv, q
If num = 1 Then prmdiv = 1: Exit Function
n = Abs(num): If n > 0 Then limit = Sqr(n) Else limit = 0
If limit <> Int(limit) Then limit = Int(limit + 1)
dv = 2: GoSub DivideIt
dv = 3: GoSub DivideIt
dv = 5: GoSub DivideIt
dv = 7
Do Until dv > limit
GoSub DivideIt: dv = dv + 4 '11
GoSub DivideIt: dv = dv + 2 '13
GoSub DivideIt: dv = dv + 4 '17
GoSub DivideIt: dv = dv + 2 '19
GoSub DivideIt: dv = dv + 4 '23
GoSub DivideIt: dv = dv + 6 '29
GoSub DivideIt: dv = dv + 2 '31
GoSub DivideIt: dv = dv + 6 '37
Loop
If n > 1 Then prmdiv = n
Exit Function
DivideIt:
Do
q = Int(n / dv)
If q * dv = n And n > 0 Then
prmdiv = dv: Exit Function
Else
Exit Do
End If
Loop
Return
End Function
finds the following solutions to the puzzle:
WHY HAYDN Prime factors of HAYDN
613 18390 2 3 5 613
523 20397 3 13 523
127 23749 11 17 127
127 24765 3 5 13 127
521 28134 2 3 3 3 521
521 29176 2 2 2 7 521
137 34798 2 127 137
739 36950 2 5 5 739
139 36974 2 7 19 139
139 38920 2 2 2 5 7 139
239 38957 163 239
947 40721 43 947
149 40975 5 5 11 149
541 42198 2 3 13 541
743 42351 3 19 743
547 43760 2 2 2 2 5 547
941 45168 2 2 2 2 3 941
149 46935 3 3 5 7 149
853 50327 59 853
359 50978 2 71 359
953 54321 3 19 953
359 54927 3 3 17 359
859 54976 2 2 2 2 2 2 859
461 63157 137 461
163 64385 5 79 163
863 67314 2 3 13 863
461 69150 2 3 5 5 461
271 70189 7 37 271
173 74390 2 5 43 173
173 78369 3 151 173
389 80912 2 2 2 2 13 389
487 82790 2 5 17 487
281 83176 2 2 2 37 281
281 85143 3 101 281
487 85712 2 2 2 2 11 487
283 86315 5 61 283
389 87914 2 113 389
193 90324 2 2 3 3 13 193
193 95342 2 13 19 193
197 95742 2 3 3 3 3 3 197
It then finds the solution to a similar puzzle: if WHY is the smallest prime factor of HAYDN. It has only two solutions:
157 54793 157 349
193 96307 193 499
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Posted by Charlie
on 2014-05-21 16:19:59 |
computer solution
