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+--- Thread: Double the Last Number (/thread-2230.html)
Double the Last Number - BitBuster - 06-Apr-2012
268435456
Double the Last Number - IceyLava108 - 06-Apr-2012
536,870,912
Double the Last Number - micronexer97 - 07-Apr-2012
1061753824
Hmm... I can see 7-5-3 which is a nice string, and the appearance of each even digit once, pretty cool number.
Double the Last Number - BitBuster - 07-Apr-2012
2123507648
I like how the digits are sort of clustered with low ones at the beginning and higher ones at the end (save for that deviant 5). I think of the 0 as acting as the break between the two classes.
Double the Last Number - IceyLava108 - 07-Apr-2012
4247015296
Umm.. no pattern.
Double the Last Number - BitBuster - 07-Apr-2012
8494030592
Say someone messed up with this whole doubling thing...at this point, would anyone notice?
Double the Last Number - ajmiam - 07-Apr-2012
Quote:8494030592
Say someone messed up with this whole doubling thing...at this point, would anyone notice?
Well, as a CS geek, I know that 2^31-1=2147483647 is the largest number that an int can hold in Java, so I know 2147483648=2^31 is a power of 2.
The number 2123507648, is not a power of 2, so someone must have messed up along the way...
Perhaps I can restore the correct sequence...
2147483648*2=4294967296.
A 10-digit number with only 5 distinct digits (2, 4, 6, 7, 9)! Also, each block of 2 digits in the first number (21, 47, 48, 36, and 48) got perfectly doubled (to 42, 94, 96, 72, and 96) without any carry from the previous block messing them up! What are the odds of that?
Double the Last Number - mathgrant - 07-Apr-2012
8589934592
Did I do it right?
Double the Last Number - BitBuster - 07-Apr-2012
17179869184
There's always this cheat sheet, which should keep us safe for at least a few more pages.
http://www.tsm-resources.com/alists/pow2.html
Double the Last Number - mathgrant - 07-Apr-2012
Quote:536,870,912
Quote:1061753824
Aha, here's the problem!
P.S. 34359738368