Huge XP lamp

The huge lamp is an item only available from the Squeal of Fortune daily event, from the "super-rare" slot. The huge lamp gives a variable amount of experience as a reward, depending on the level of the skill. It will give double the experience earned from the large lamp. It appears to be a large lamp studded with rubies.

Below is the data gathered so far about the experience gained from this lamp:

Experience Gained Formula
This is a polynomial function where x=level.

$$663.796486 + 14.4355241x + 5.8695973x^2 - 0.119998437x^3 + 0.00142607098x^4$$