Hint

There are actually five terms here, 'cause we're starting at n = 0.

Hint

There will be seven very odd terms.

Hint

Factoring out a 3 may help.

Hint

Multiply by 4 at the very end.

Hint

Once again, multiply by 12 last.

Hint

Write 'em out.

Hint

Don't wait so long to multiply the 3 this time.

Hint

Use 2 as a factor in your rule.

Hint

Use 2 as a constant multiple.