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 Palindromes and Divisibility (Posted on 2015-10-16)
How many positive palindromes less than 20150 are divisible by 7?

 No Solution Yet Submitted by K Sengupta No Rating

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 computer solution | Comment 1 of 3
7
77
161
252
343
434
525
595
616
686
707
777
868
959
1001
1771
2002
2772
3003
3773
4004
4774
5005
5775
6006
6776
7007
7777
8008
8778
9009
9779
10101
10801
11011
11711
12621
13531
14441
15351
16261
16961
17171
17871
18081
18781
19691
101101
108801
111111
118811
121121
128821
131131
138831
141141
148841
151151
158851
161161
168861
171171
178871
181181
188881
191191
198891

A total of 67 such numbers.

The numbers were sorted into ascending order after running

DefDbl A-Z
Dim crlf\$

Form1.Visible = True

Text1.Text = ""
crlf = Chr\$(13) + Chr\$(10)

For n = 1 To 201
ns\$ = LTrim(Str(n))
nsr\$ = ""
For i = 1 To Len(ns)
nsr = Mid(ns, i, 1) + nsr
Next
n1 = Val(ns + Mid(nsr, 2)): n2 = Val(ns + nsr)
If n1 Mod 7 = 0 Then Text1.Text = Text1.Text & mform(n1, "#####0") & crlf: ct = ct + 1
If n2 Mod 7 = 0 Then Text1.Text = Text1.Text & mform(n2, "#####0") & crlf: ct = ct + 1
Next n

Text1.Text = Text1.Text & ct & crlf & " done"

End Sub

Function mform\$(x, t\$)
a\$ = Format\$(x, t\$)
If Len(a\$) < Len(t\$) Then a\$ = Space\$(Len(t\$) - Len(a\$)) & a\$
mform\$ = a\$
End Function

 Posted by Charlie on 2015-10-16 10:50:58

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