Problem 025

luke · Post by **luke** » Sun Jan 27, 2008 3:23 pm

a low level question about problem25...
How can I put my solution for problem25 (a 1000 digit number) in an eighteen chars form?......

thanks
luke

stijn263 · Post by **stijn263** » Sun Jan 27, 2008 3:26 pm

put in the index number

luke · Post by **luke** » Sun Jan 27, 2008 5:35 pm

ok,
I'm sorry for the stupid question....I haven't read carefully problem description....

thanks....

luca

nahkh · Post by **nahkh** » Sun Feb 24, 2008 5:52 pm

Nah, the question is a little ambiguous. They do ask which Fibonacci number is the first to have 1000 digits. The 1000-digit number does seem the natural answer.

euler · Post by **euler** » Sun Feb 24, 2008 6:49 pm

The preceding line removes any ambiguity:

The 12th term, F₁₂, is the first term to contain three digits.

What is the first term in the Fibonacci sequence to contain 1000 digits?

Can it mean anything other than the first value of n for which F_n contains one-thousand digits?

pdunning · Post by **pdunning** » Thu Sep 25, 2008 6:29 pm

I have a problem submitting the answer to problem 25. The answer, as specified has 1000 digits, but how do I submit it when the input field can't hold nearly enough characters?

daniel.is.fischer · Post by **daniel.is.fischer** » Thu Sep 25, 2008 6:33 pm

Are you sure you mean problem 20: "Find the sum of the digits in the number 100!"? Probably a typo and you meant problem 25: "What is the first term in the Fibonacci sequence to contain 1000 digits?". You're not supposed to enter F_n but n. That easily fits in the answer box

pdunning · Post by **pdunning** » Thu Sep 25, 2008 6:37 pm

I did mean problem 25, sorry, and thanks for the help

daniel.is.fischer · Post by **daniel.is.fischer** » Thu Sep 25, 2008 7:46 pm

No problem, and you're welcome.

jozhan · Post by **jozhan** » Tue Dec 09, 2008 9:37 pm

I think I solved problem 25 about the fibonacci number with thousand digits, but I'm unsure on the format in which the answer must be given.
Should I give the thousand digits or should I give the index of the fibonacci number? Must I do something with an F and subscript? All I'm doing doen't seem to work, while I'm pretty sure I've got it right.
Thank you in advance
Jozef

hk · Post by hk » Tue Dec 09, 2008 9:43 pm

The index

jozhan · Post by **jozhan** » Tue Dec 09, 2008 10:12 pm

thanks

waynecolvin · Post by **waynecolvin** » Thu Apr 15, 2010 6:27 pm

I got mixed up on the thousand digits vs. sequence index too. Actually index didn't occur to me at all the way it was phrased and I accidentally computed a 1001 digit number at first anyway!

Rhawk187 · Post by **Rhawk187** » Wed Jun 30, 2010 8:41 pm

I'm a little confused bout the answer. The way I read it, it is supposed to be the full 1000 digit answer, but when I try to enter it into the answer field it limits me to closer to 30 characters, any suggestions?

DJohn · Post by **DJohn** » Wed Jun 30, 2010 8:50 pm

There's already a thread for this problem: viewtopic.php?f=50&t=1296

As the example says, the twelth term is the first to have three digits. In that case, the answer would be 12, not 144.

Rhawk187 · Post by **Rhawk187** » Wed Jun 30, 2010 10:13 pm

Sorry about that, I search for Problem 25, but I guess the leading 0 on the thread got me.

That makes sense though, I don't know why I didn't think of that sooner.

namekuseijin · Post by **namekuseijin** » Mon Oct 11, 2010 5:28 pm

Hi, just solved this one and was able to read some of the solutions in the official (locked) thread. too bad I can't show off my code...

I know in here we can't give away the solution, but oh my!, never thought mankind has lost so much common sense math-wise! Come on, there surely is no need to count characters in a big string just to find out how many digits some number got! And yet so many of the solutions are that stupid! Since the thread is locked, I felt that bad to even register here in the forum (why not single account BTW?) to let some steam off...

can I give at least an innocent clue? first number with 2 digits is 10^1, first with 3 is 10^2... you can see a pattern here, can't you?

rayfil · Post by **rayfil** » Mon Oct 11, 2010 5:53 pm

And yet so many of the solutions are that stupid!

Were they ALL that stupid? Were some of them good?

And was yours significantly better and different than the best ones? If you strongly believe that after checking that forum in detail, send me a PM about it and we could then consider to reopen the forum for you. (Make sure you are correct, otherwise you may not be taken seriously in the future.)

In your opinion, if that thread had not been locked, how many more "stupid" solutions would have continued to be posted???

namekuseijin · Post by **namekuseijin** » Mon Oct 11, 2010 6:05 pm

some of the replies were quite good, particularly the pen-paper-and-brain ones.

But I agree with you letting it open for more of the same stupidity is bad. My solution is in Scheme and while I did see quite a few Lisp and Scheme solutions, they were mostly as horrid as the rest (plus some of them look like Lisp written by java programmers). I've not looked into all the thread in detail though. I'll send you the solution by PM anyway...

zcxvbn · Post by **zcxvbn** » Mon Oct 11, 2010 10:41 pm

namekuseijin wrote:some of the replies were quite good, particularly the pen-paper-and-brain ones.

But I agree with you letting it open for more of the same stupidity is bad. My solution is in Scheme and while I did see quite a few Lisp and Scheme solutions, they were mostly as horrid as the rest (plus some of them look like Lisp written by java programmers). I've not looked into all the thread in detail though. I'll send you the solution by PM anyway...

Keep in mind that this is one of the earlier problems, which are generally more accessible and hence there is less of a need to have a 'good' solution. Besides, there is a very short constant-time solution in the first page of the thread, and I doubt yours will be any better

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