For a number written in Roman numerals to be considered valid there are basic rules which must be followed. Even though the rules allow some numbers to be expressed in more than
one way there is alw...
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其他好文 时间：
2015-07-24 22:42:34
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290
For a number written in Roman numerals to be considered valid there are basic rules which must be followed. Even though the rules allow some numbers to be expressed in more than
one way there is alw...
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其他好文 时间：
2015-07-24 18:29:36
阅读次数：
128
A natural number, N, that can be written as the sum and product of a given set of at least two natural numbers, {a1, a2, ... , ak}
is called a product-sum number: N = a1 + a2 + ... + ak = a1 × a2 × ...
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其他好文 时间：
2015-07-23 23:48:41
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140
The smallest number expressible as the sum of a prime square, prime cube, and prime fourth power is 28. In fact, there are exactly four numbers below fifty that can be expressed
in such a way:
28...
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其他好文 时间：
2015-07-23 21:50:50
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210
In the game, Monopoly, the standard board is set up in the following way:
GO
A1
CC1
A2
T1
R1
B1
CH1
B2
B3
JAIL
H2
C1
T2
U1
H1
C2
CH3
C3
R4
...
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其他好文 时间：
2015-07-22 16:29:45
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94
The minimal path sum in the 5 by 5 matrix below, by starting in any cell in the left column and finishing in any cell in the right column, and only moving up, down, and right, is
indicated in red an...
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其他好文 时间：
2015-07-21 17:10:05
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145
A common security method used for online banking is to ask the user for three random characters from a passcode. For example, if the passcode was 531278, they may ask for the 2nd,
3rd, and 5th chara...
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其他好文 时间：
2015-07-20 16:47:38
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118
Let p(n) represent the number of different ways in which n coins can be separated into piles. For example, five coins can be separated into piles in exactly seven
different ways, so p(5)=7.
...
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其他好文 时间：
2015-07-19 16:35:22
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181
It is possible to write five as a sum in exactly six different ways:
4 + 1
3 + 2
3 + 1 + 1
2 + 2 + 1
2 + 1 + 1 + 1
1 + 1 + 1 + 1 + 1
How many different ways can one hundred be written as a su...
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其他好文 时间：
2015-07-18 18:41:52
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94
It is possible to write ten as the sum of primes in exactly five different ways:
7 + 3
5 + 5
5 + 3 + 2
3 + 3 + 2 + 2
2 + 2 + 2 + 2 + 2
What is the first value which can be written as the sum o...
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其他好文 时间：
2015-07-18 18:40:05
阅读次数：
118
