奇聞：法國天才７２．４秒算出２００位數(shù)的１３次方根

武淵濤

French “mathlete” Alexis Lemaire showed off his rare mental agility Thursday, breaking the world record kept by himself after working out in his head the 13th root of a random 200-digit number in just 72.4 seconds.

Lemaire, a 27-year-old doctoral student in artificial intelligence from Reims, near Paris, was presented with the randomly-picked 200-digit number by a computer, which displayed the figure over 17 lines on the screen.

Lemaire then took just over a minute to identify two quadrillion, 397 trillion, 207 billion, 667 million, 966 thousand, 701 as the 13th root.

In other words, the number multiplied by itself 13 times produces the 200 digit number originally generated by the computer.

“The first digit is very easy, the last digit is very easy, but the inside numbers are extremely difficult,” the mental gymnast, who says he doesnt consider himself a nerd or a geek, said.

Lemaire, who sports a beard and glasses under thickly-matted eyebrows and a furrowed brow, previously performed the feat in 77 seconds and has been working at the 13th root problem for years, repeatedly eroding his best time.

“I use an artificial intelligence system which I use on my own brain instead of on a computer,” he explained, matter-of-factly.

“Personally, I believe most people can do it but I have also a high-speed mind. My brain works sometimes very, very fast.”

上周四，法國“數(shù)學(xué)天才”亞歷克西斯·勒麥爾展示了其罕見的心算本領(lǐng)，他以72.4秒心算出一個(gè)隨機(jī)抽取的200位數(shù)的13次方根，打破了由他本人保持的世界紀(jì)錄。

27歲的勒麥爾來自巴黎附近的蘭斯市，是人工智能專業(yè)的一名博士生。這個(gè)由計(jì)算機(jī)隨機(jī)抽取的200位數(shù)在屏幕上顯示了整整17行。

而勒麥爾只用了一分多鐘的時(shí)間就算出了這一長串?dāng)?shù)字的13次方根，答案是2397207667966701。

換句話說，這個(gè)數(shù)字的13次方就是計(jì)算機(jī)抽取的那個(gè)200位數(shù)。

勒麥爾說：“（在計(jì)算過程中，）確定第一個(gè)和最后一個(gè)數(shù)字非常容易，但算出中間的數(shù)字相當(dāng)困難?！边@位數(shù)學(xué)天才說自己并不是個(gè)“書呆子”或“怪人”。

勒麥爾留著絡(luò)腮胡，戴著副眼鏡，眉毛濃密，有抬頭紋。勒麥爾之前的紀(jì)錄是77秒。多年來，他一直研究心算200位數(shù)的13次方根問題，并多次打破自己保持的紀(jì)錄。

他不動(dòng)聲色地解釋說：“我是用一個(gè)人工智能系統(tǒng)計(jì)算出結(jié)果的，只不過我在大腦中運(yùn)用這個(gè)系統(tǒng)，而不是在計(jì)算機(jī)中?！?/p>

“我相信大多數(shù)人都能算出一個(gè)200位數(shù)的13次方根，只是我的速度稍快一些。我的大腦有時(shí)運(yùn)轉(zhuǎn)得相當(dāng)快。”