How would the purchase of the louisiana territory fromfrance have encourage american settlers to later travel to oregon and california

The purchase of the Louisiana territory from France is not related with the later annexion of California, which was during that time part of Spain, and then it passed to Mexico.

About Oregon, the purchase expanded American territories to the northwest, carrying the American border next to the Oregon territory, which was a disputed area with Great Britain.

What the Louisiana Purchase actually generated was the affirmation of the doctrine of manifest destiny, by which the United States began to try to extend its territories to the Pacific Ocean; which, looking at the locations of California and Oregon, makes us think that this may have been a secondary relationship between the Louisiana Purchase and the subsequent acquisitions of California and Oregon.