Erdős-Nicolas numbers: Difference between revisions

</pre>

=={{header|C++}}==

{{trans|ALGOL 68}}

<syntaxhighlight lang="cpp">#include <iomanip>

#include <iostream>

#include <vector>

int main() {

const int max_number = 100000000;

std::vector<int> dsum(max_number + 1, 1);

std::vector<int> dcount(max_number + 1, 1);

for (int i = 2; i <= max_number; ++i) {

for (int j = i + i; j <= max_number; j += i) {

if (dsum[j] == j) {

std::cout << std::setw(8) << j

<< " equals the sum of its first " << dcount[j]

<< " divisors\n";

}

dsum[j] += i;

++dcount[j];

}

}

}</syntaxhighlight>

{{out}}

<pre>

24 equals the sum of its first 6 divisors

2016 equals the sum of its first 31 divisors

8190 equals the sum of its first 43 divisors

42336 equals the sum of its first 66 divisors

45864 equals the sum of its first 66 divisors

714240 equals the sum of its first 113 divisors

392448 equals the sum of its first 68 divisors

1571328 equals the sum of its first 115 divisors

61900800 equals the sum of its first 280 divisors

91963648 equals the sum of its first 142 divisors