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computing teh last digits without computing the number - Printable Version

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computing teh last digits without computing the number - deepinlife - 02/23/2009

guys how can i compute teh last digit of a number , resulting from tetration without computing the real number..
for example ...5||2 = 2^65536...how can i get the last digit of that number without computing it..teh last 8 digits for example ?


RE: computing teh last digits without computing the number - bo198214 - 02/23/2009

deepinlife Wrote:guys how can i compute teh last digit of a number , resulting from tetration without computing the real number..
for example ...5||2 = 2^65536...how can i get the last digit of that number without computing it..teh last 8 digits for example ?
See here.

Where do you guys get those questions? Is it a homework exercise or so? Wink


RE: computing teh last digits without computing the number - andydude - 02/24/2009

bo198214 Wrote:Where do you guys get those questions? Is it a homework exercise or so? Wink

These questions are very common in contests, like the Putnam Competition.

Andrew Robbins


RE: computing teh last digits without computing the number - deepinlife - 02/24/2009

it is a problem in a site :
http://projecteuler.net/index.php?section=problems&id=214