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Sum Power Digit Determination (Posted on 2014-07-12) Difficulty: 3 of 5
Determine the last digit of:

12 + 23 + 34 + 45 + .......+ 20142015

No Solution Yet Submitted by K Sengupta    
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Solution computer solution | Comment 1 of 4
DEFDBL A-Z
FOR n = 1 TO 2014
    t = t + modpow(n, n + 1, 10000)
NEXT
PRINT t MOD 10000
_clipboard$=str$(t mod 10000)

FUNCTION modpow (b, p, m)
answ = 1
FOR i = 1 TO p
    answ = (answ * b) MOD m
NEXT
modpow = answ
END FUNCTION


finds 
 
 4311
 
as the last four digits of the number, so the last digit is a 1

  Posted by Charlie on 2014-07-12 12:30:34
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