Arithmetic numbers: Difference between revisions
Add C# implementation
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(Add C# implementation) |
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Number of composite arithmetic numbers <= 1228663: 905043
</pre>
=={{header|C#}}==
{{trans|Java}}
<syntaxhighlight lang="C#">
using System;
using System.Collections.Generic;
using System.Linq;
public class ArithmeticNumbers
{
public static void Main(string[] args)
{
int arithmeticCount = 0;
int compositeCount = 0;
int n = 1;
while (arithmeticCount <= 1_000_000)
{
var factors = Factors(n);
int sum = factors.Sum();
if (sum % factors.Count == 0)
{
arithmeticCount++;
if (factors.Count > 2)
{
compositeCount++;
}
if (arithmeticCount <= 100)
{
Console.Write($"{n,3}{(arithmeticCount % 10 == 0 ? "\n" : " ")}");
}
if (new[] { 1_000, 10_000, 100_000, 1_000_000 }.Contains(arithmeticCount))
{
Console.WriteLine();
Console.WriteLine($"{arithmeticCount}th arithmetic number is {n}");
Console.WriteLine($"Number of composite arithmetic numbers <= {n}: {compositeCount}");
}
}
n++;
}
}
private static HashSet<int> Factors(int number)
{
var result = new HashSet<int> { 1, number };
int i = 2;
int j;
while ((j = number / i) >= i)
{
if (i * j == number)
{
result.Add(i);
result.Add(j);
}
i++;
}
return result;
}
}
</syntaxhighlight>
{{out}}
<pre>
1 3 5 6 7 11 13 14 15 17
19 20 21 22 23 27 29 30 31 33
35 37 38 39 41 42 43 44 45 46
47 49 51 53 54 55 56 57 59 60
61 62 65 66 67 68 69 70 71 73
77 78 79 83 85 86 87 89 91 92
93 94 95 96 97 99 101 102 103 105
107 109 110 111 113 114 115 116 118 119
123 125 126 127 129 131 132 133 134 135
137 138 139 140 141 142 143 145 147 149
1000th arithmetic number is 1361
Number of composite arithmetic numbers <= 1361: 782
10000th arithmetic number is 12953
Number of composite arithmetic numbers <= 12953: 8458
100000th arithmetic number is 125587
Number of composite arithmetic numbers <= 125587: 88219
1000000th arithmetic number is 1228663
Number of composite arithmetic numbers <= 1228663: 905043
</pre>
=={{header|C++}}==
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