It seems like you are providing a sequence of numbers: 1, -3, 12. Could you clarify how you want me to work with this sequence? Here are a few possibilities:

1. Are you looking for the next number in the sequence?
2. Are you asking for a pattern or formula?
3. Do you need a mathematical operation on these numbers?
4. Is this part of a larger problem?

Let me know how you'd like to proceed!

Sample questions to consider:

1. What could be the next number in this sequence?
2. Is there a common difference or ratio between these numbers?
3. Could this be part of a geometric or arithmetic sequence?
4. How would we find the rule governing this sequence?
5. What mathematical properties could these numbers share?

Tip: When working with sequences, always look for a consistent pattern (addition, subtraction, multiplication, division, etc.) between terms!