Problem 30
Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:
1634 = 14 + 64 + 34 + 44
8208 = 84 + 24 + 04 + 84
9474 = 94 + 44 + 74 + 44...
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其他好文 时间：
2014-08-21 09:48:04
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251
Problem 29
Consider all integer combinations of ab for 2 ≤ a ≤ 5 and 2 ≤ b ≤ 5:
22=4, 23=8, 24=16, 25=32
32=9, 33=27, 34=81, 35=243
42=16, 43=64, 44=256, 45=1024
52=25, 53=125, 54=625, 55=312...
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其他好文 时间：
2014-08-21 08:26:53
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177
Problem 28
Starting with the number 1 and moving to the right in a clockwise direction a 5 by 5 spiral is formed as follows:
21 22 23 24 25
20 7 8 9 10
19 6 1 2 11
18 5 4 3 12
17 16...
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其他好文 时间：
2014-08-20 18:04:12
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237
A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given:
1/2
=
0.5
1/3
=
0.(3)
1/4
=
0.25
1/5...
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其他好文 时间：
2014-08-20 16:25:32
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157
Euler discovered the remarkable quadratic formula:
n² + n + 41
It turns out that the formula will produce 40 primes for the consecutive values n = 0 to 39. However, when n = 40, 402 + 40 + 41 = 40...
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其他好文 时间：
2014-08-20 16:21:12
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244
问题描述：
A permutation is an ordered arrangement of objects. For example, 3124 is one possible permutation of the digits 1, 2, 3 and 4. If all of the permutations are listed numerically or alphabeti...
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其他好文 时间：
2014-06-10 06:13:21
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299
问题描述：
The Fibonacci sequence is defined by the recurrence relation:
Fn = Fn1 + Fn2,
where F1 = 1 and F2 = 1.
Hence the first 12 terms will be:
F1 = 1
F2 = 1
F3 = 2
F4 = 3
F5 = 5
F6 = 8
...
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其他好文 时间：
2014-06-10 06:10:06
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307
A perfect number is a number for which the sum of its proper divisors is exactly equal to the number. For example, the sum of the proper divisors of 28 would be 1 + 2 + 4 + 7 + 14 = 28, which means th...
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其他好文 时间：
2014-06-08 04:05:14
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315
You are given the following information, but you may prefer to do some research for yourself.
1 Jan 1900 was a Monday.Thirty days has September,
April, June and November.
All the rest have thirty...
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其他好文 时间：
2014-06-07 13:56:52
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166
By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.
3
7 4
2 4 6
8 5 9 3
That is, 3 + 7 + 4 + 9 = 23.
Find th...
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其他好文 时间：
2014-06-07 13:45:25
阅读次数：
189
