Pandigital products
Problem 32
We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once; for example, the 5-digit number, 15234, is 1 through 5 pandigit...
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其他好文 时间：
2015-07-25 22:59:43
阅读次数：
141
Sub-string divisibility
Problem 43
The number, 1406357289, is a 0 to 9 pandigital number because it is made up of each of the digits 0 to 9 in some order, but it also has a rather interesting sub-str...
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其他好文 时间：
2015-07-25 18:28:50
阅读次数：
164
Self powers
Problem 48
The series, 11+22+33+...+1010=104050713171^1 + 2^2 + 3^3 + ... + 10^{10} = 10405071317.Find the last ten digits of the series, 11+22+33+...+100010001^1 + 2^2 + 3^3 + ... + 1000...
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编程语言 时间：
2015-07-24 01:30:34
阅读次数：
201
Champernowne’s constant
Problem 40
An irrational decimal fraction is created by concatenating the positive integers:0.123456789101112131415161718192021…It can be seen that the 12th digit of the fract...
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其他好文 时间：
2015-07-18 02:06:56
阅读次数：
158
Digit factorials
Problem 34
145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145.Find the sum of all numbers which are equal to the sum of the factorial of their digits.Note: as 1! = 1 and 2...
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其他好文 时间：
2015-07-09 00:50:46
阅读次数：
166
1000-digit Fibonacci number
Problem 25
The Fibonacci sequence is defined by the recurrence relation:
Fn = Fn?1 + Fn?2, where F1 = 1 and F2 = 1.
Hence the first 12 terms will be:
F1 = 1
F...
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编程语言 时间：
2015-06-18 09:52:36
阅读次数：
175
Reciprocal cycles
Problem 26
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...
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编程语言 时间：
2015-06-17 21:45:33
阅读次数：
147
Quadratic primes
Problem 27
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. Howe...
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编程语言 时间：
2015-06-17 21:37:46
阅读次数：
149
Distinct powers
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, 5...
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编程语言 时间：
2015-06-17 21:36:18
阅读次数：
220
Names scores
Problem 22
Using names.txt (right click and 'Save Link/Target As...'), a 46K text file containing over five-thousand first names,
begin by sorting it into alphabetical order. ...
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编程语言 时间：
2015-06-17 21:33:53
阅读次数：
223
