// Created by Krishna Teja Yeluripati changed a little by Arnoud Loschnig function challenge27() { var a = [], b = "e",c=0; alert("...the beautiful code by:\n \n Krishna Teja Yeluripati\n \n which code is inspiringly quick and therefor studied by me. I even dared to make it more perfect 😉...Arnoud Loschnig \n \n ");//c = 0; // if (Number.isSafeInteger(b)) // document.write("

Perfect Numbers from 1 to " + b + ":"); // else document.write("

Perfect Numbers from 1 to " + (b = Math.pow(2, 100) - 1) + ":

"); for (var d = 0; ; d++) { var e = Math.pow(2, d - 1); var f = Math.pow(2, d) - 1; if (!Number.isSafeInteger(e * f)) break; if (e * f " + a [g] + "
"); document.write("
"); } function isPrime(h) { if (h === 0 || h === 1) return false; for (var i = 2; i < h; i++) if (h % i === 0) return false; return true; } function allFactors(j) { var k = []; for (var l = 1; l < Math.sqrt(j); l++) if (j % l === 0 && l != 1) k.splice(0, 0, l, j / l); document.getElementById ("dv" + j).innerHTML = " = " + k.sort(function(a, b) { return a - b; }).reduce(function(a, b) { return a + " + " + b + " "; }, "1 "); var val = document.getElementById ("btn" + j).value ='Swipe'; var val = "Swipe("+ j +")"; document.getElementById ("btn" + j).setAttribute('onclick',val); Factors(j); } function Factors(j) { var k =[]; document.getElementById ("dv" + j).innerHTML += "

The calculations with the factors are:
"; for (var l = 1; l < Math.sqrt(j); l++) if (j % l === 0) document.getElementById ("dv" + j).innerHTML +="
" + l + " x " + j/l + " = " + j + "
"; document.getElementById ("dv" + j).innerHTML += "
"; var val = document.getElementById ("btn" + j).value ='Clear'; var val = "Clear("+ j +")"; document.getElementById ("btn" + j).setAttribute('onclick',val); } function Clear(j){ document.getElementById ("btn" + j).value = "I liked it 👍"; document .getElementById ("dv" +j).innerHTML = ""; var val = "allFactors("+ j +")"; document.getElementById ("btn" + j).setAttribute('onclick',val); }

Study 01 - challenge 27