110_perfect.js

function ExprArray(n,v){for(var i=0;i<n;i++)this[i]=""+v}
function perfect(n){print("The perfect numbers up to "+n+" are:");var sumOfDivisors=new ExprArray(n+1,1);for(var divisor=2;divisor<=n;divisor++){for(var j=divisor+divisor;j<=n;j+=divisor)sumOfDivisors[j]+=" + "+divisor;if(eval(sumOfDivisors[divisor])==divisor)print(""+divisor+" = "+sumOfDivisors[divisor])};print("That's all.")};print("\nA number is 'perfect' if it is equal to the sum of its");print("divisors (excluding itself).\n");perfect(500)