SOURCE

var classId = 2;
var levelExpAll = 0;
for(i=1;i<=19;i++){
    var level = LevelConvert(classId,i);
    levelEXP = LevelExp(level);
    levelExpAll += LevelExp(level);
    //console.log(level);
    //console.log(levelEXP);
    console.log(levelExpAll);
};

function LevelExp(level){
        var i = level+1;
        var a = 5;//基本值
        var b = 20;//补正值
        var c = 1;//增加度A
        var d = 30;//增加度B
        var expAll = Math.round(a*(Math.pow(i-1, 0.9+c/250))*i*
    (i+1)/(6+Math.pow(i,2)/50/d)+(i-1)*b);
        var expPre = Math.round(a*(Math.pow(i-2, 0.9+c/250))*(i-1)*
    (i)/(6+Math.pow(i-1,2)/50/d)+(i-2)*b);
        var exp = expAll-expPre;

    return exp;

};

function LevelConvert(classId, levelId){
    var level = 1;
    switch (classId){
        case 2: 
            level = levelId;
            break;
        case 3:
            level = levelId+14;
            break;
        case 4:
            level = levelId+28;
            break;
        case 5:
            level =  levelId+42;
            break;
        case 6:
            level =  levelId+56;
            break;
        case 7:
            level =  levelId+70;
            break;
        case 8:
            level =  levelId+84;
            break;
    };
    return level;
};