Problem Twenty One

twenty-one.js

var results = [],
    a,
    b;

function divisors( a ) {
    var divisor = [];
    for (var i = 1; i <= a / 2; i++) {
        if ( a % i === 0 ) {
            divisor.push( i );
        }
    }
    
    if ( divisor.length > 1 ) {
        return sum( divisor );
    }
}

function sum( numbers ) {
    var product = 0;
    for (var i = 0; i < numbers.length; i++) {
        product += numbers[i];
    }
    return product;
}

for (var i = 1; i <= 10000; i++) {
    a = divisors( i );
    
    if ( a ) {
        b = divisors( a );
        if ( b === i && b !== a && results.indexOf( i ) === -1 ) {
            results.push( i, a );
        }
    }
}

document.write( sum( results ) );