My brain hurts. Can't figure this out, so bad at for loops!

You have a few issues here.

First, the each section of thefor loop should be treated as it's own statement. In JavaScript, a statement that lives on the same line as another statement must end in a semicolon:

for (var i = 4; i <= 156; i++) {
   // code for loop
}

If you notice, in the example, each statement (with the exception of the last one) ends in a semicolon.

Second, when creating a variable within a loop, you should specify what type of variable it is with either the var keyword. You can also declare the variable outside of the loop, though it is common to just use a var in the for loop itself:

var i = 4;

for (i; i <= 156; i++) {
    // code for loop
}

// or 

for (var i = 4; i <= 156; i++) {
   // code for loop
}

Third, we want to increment the value of i which is where the i++ comes into play. Your example looks like a mistype using the number 1 instead of the variable i. Look at the examples above to see.

Lastly, the challenge is looking for you to print the numbers 4 all the way to/and including the number 156. To do this, you will want to use <= as in the examples above. Since the loop automatically increments the value for you, you simply need to log the value of the variable itself by doing this (inside the for loop):

console.log(i);

Does that help?