Recently riding my motorcycle on highway 101, south of San Francisco I've noticed big advertisement poster:
(I stole the picture from some later post in spanish who also found the number. When I worked on this, google search did not find any results for this puzzle).
Out of curiosity I decided to find out what it is. Since I am still learning Haskell, I decided that that would be nice Haskell exercise. It was nice exercise indeed, in course of which I have learned more about Haskell and things like Rabin-Miller Probable Prime Test and Spigot Algorithm
Well, I did it and was able to find number. I went to the site, expecting something exiting, but it just says "Congratulations. You've made it to level 2" and offers next puzzle. Frankly, without knowing what it is about (I guess this is a new way to screen employees) I am not very inclined to spend more time solving their puzzles. Also, the next puzzle they offer is of kind I detest: trying to find next number in sequence. I hate when people ask something like this on interviews.
So, being dissapointed for being sent to wild goose chanse without any gratification, I decided to share the answer to their first problem. I hope search engines pick up this page soon and they will have more potential candidates knocking on the door of their second level.
The prime they were asking for is 7427466391.
I will apprecite if somebody who will get through all their puzzles will tell me what it was about.
UPDATE (September 2004): I would like to thank all of you who took their time to let me know that this is Google recruitment campaign. After solving second part of the puzzle I was able to see that for myself. So if you are looking for the answers: your got them right here. You are welcome to read the rest of my blog (or even subscribe to new posts with RSS).
Hi! I'm Carl. found your blog while searching for "first 10 digit prime found in consecutive digits of e".com.
I was reading SEED magazine and saw this small article re jobs. you are right, it is a recruitment campaign.
Here's the article, but the first site is already down.
This summer, Google placed cryptic billboards in Harvard Square and Silicon Valley that read simply: "first 10 digit prime found in consecutive digits of e".com. Solve the quiz - that's 7427466391.com - enter the website, and you're presented with another problem whose solution leads to yet another site. Get it right again, and you're triumphantly linked into Google Labs and, Mazel Tov (their words), invited to submit a resume.
In a short time, Google has acquired in excess of 100 doctors of science-though they're all but opaque about the actual number-with the promise that Ph.D.s will have the independence to conduct their own research at least one dat a week (and get free food, and massages, natch). But it's the recruiting techniques that we're loving: attract intelligence with intelligence - JR
On February 15th, 2006 01:16 am (UTC), (Anonymous) replied:
Wow Sean, it looks like someone needs a crash course in math. 1,000,000,002 has the factors 2, 3, 43, 983, 3943. Since it has factors other then 1 and itself, it can't be prime. According to your logic, 12 would also be a prime number which it's not but 17 is.