Can you find the next number in this sequence? - Alex Gendler

翻译人员: Liyu Liu 校对人员: Lipeng Chen

These are the first five elements of a number sequence.

这些是一个数列最开始的五个数字。

Can you figure out what comes next?

你能想出下一个数字是什么吗？

Pause here if you want to figure it out for yourself.

如果你想要自己先想清楚的话 就在这里暂停一下。

Answer in: 3

答案倒数 3

Answer in: 2

Answer in: 1

答案倒数 2

答案倒数 1

There is a pattern here,

这个数列有一个规律，

but it may not be the kind of pattern you think it is.

然而这个规律可能不是你所想的那样。

Look at the sequence again and try reading it aloud.

重新再看一下这个数列。

并尝试读出声来。

Now, look at the next number in the sequence.

现在，让我们来看这一数列的下一个数字。

3, 1, 2, 2, 1, 1.

3，1，2，2，1，1

Pause again if you'd like to think about it some more.

如果你需要多思考一下的话 可以再暂停一下。

Answer in: 3

答案倒数 3

Answer in: 2

答案倒数 2

Answer in: 1

答案倒数 1

This is what's known as a look and say sequence.

这就是所谓的外观数列，

Unlike many number sequences,

和其它的数字数列不同，

this relies not on some mathematical property of the numbers themselves,

这个数列的规律并不依靠于 数字自身的的数学属性，

but on their notation.

而是数字的表示法。

Start with the left-most digit of the initial number.

从初始数字的最左数位开始读起。

Now, read out how many times it repeats in succession

现在读出它连续重复的次数，

followed by the name of the digit itself.

然后再读出这一数字。

Then move on to the next distinct digit and repeat until you reach the end.

下一个数位的读法也是依此类推。

直到读完最后一位。

So the number 1 is read as "one one"

所以数字1读作“一个一”，

和我们写数字十一的方法一样。

written down the same way we write eleven.

Of course, as part of this sequence, it's not actually the number eleven,

自然，作为这个数列的一部分，

11并不是真正的数字十一，

but 2 ones,

而是“两个一”，

因此我们又写作21。

which we then write as 2 1.

That number is then read out as 1 2 1 1,

而这个数字读出来是1 2 1 1，

which written out we'd read as one one, one two, two ones, and so on.

而1211写出来又可读作 一个一、一个二、二个一，

以此类推。

These kinds of sequences were first analyzed by mathematician John Conway,

这个数列最初是由数学家 John Conway 所发现，

who noted they have some interesting properties.

他注意到了这一数列一些很有趣的属性。

For instance, starting with the number 22, yields an infinite loop of two twos.

比如从数字22开始， 这一数列会生成的“二个二”的无穷循环。

But when seeded with any other number,

但如果我们从其他数字开始的话，

the sequence grows in some very specific ways.

这个数列就会以一些特殊的方式展开。

Notice that although the number of digits keeps increasing,

请注意，虽然这些数字的位数数量在不断增长，

the increase doesn't seem to be either linear or random.

这些增长似乎并不是线性的或随机的。

In fact, if you extend the sequence infinitely, a pattern emerges.

事实上，如果你把这个数列无限扩大，

规律就会浮现出来。

The ratio between the amount of digits in two consecutive terms

相邻两个数字的数位数量之间的比例，

gradually converges to a single number known as Conway's Constant.

会逐渐趋近 一个被称为“Conway常数”的数字。

This is equal to a little over 1.3,

这一数字会比1.3稍大一点，

meaning that the amount of digits increases by about 30%

也就是说，数列中每生成下一项数字，

with every step in the sequence.

数位的数量大约增长30%。

What about the numbers themselves?

那么，那些数字本身如何呢？

That gets even more interesting.

这就更加有趣了。

Except for the repeating sequence of 22,

除了22这一无限循环的数列，

every possible sequence eventually breaks down into distinct strings of digits.

每一个可能的数列最终会 被分解成不同的数位字符串。

No matter what order these strings show up in,

不论这些字符串以怎样的顺序出现，

each appears unbroken in its entirety every time it occurs.

它们都会不断延续下去。

Conway identified 92 of these elements,

Conway 分析了92个字符串，

all composed only of digits 1, 2, and 3,

所有的字符串只包含数字1、2和 3

as well as two additional elements

以及其他两个变化的字符串，

whose variations can end with any digit of 4 or greater.

它们以大于或等于4的数字结尾。

No matter what number the sequence is seeded with,

无论从哪一个数字开始这一数列，

eventually, it'll just consist of these combinations,

数列最终都会包含以上这些字符串的组合。

with digits 4 or higher only appearing at the end of the two extra elements,

大于或等于4的数字 只出现在两个变化字符串的末尾，

if at all.

如果出现的话。

Beyond being a neat puzzle,

除了作为一个工整有序的数字谜题之外，

the look and say sequence has some practical applications.

外观数列也被应用到实际中。

For example, run-length encoding,

以游程编码为例，

a data compression that was once used for television signals and digital graphics,

它从前被运用到电视信号和 数码图像的数据压缩上。

is based on a similar concept.

游程编码也是建立在一个相似的概念上，

The amount of times a data value repeats within the code

在编码中， 数据出现的次数被记作数据值。

is recorded as a data value itself.

Sequences like this are a good example of how numbers and other symbols

这样的数列就是一个很好的例子，

表现数字和其他符号是 怎样在多层次方面传达含义的。

can convey meaning on multiple levels.