Policy Question about using formulas

So... starting to scratch some headway into this fantastic program. I had a question about accepted use of using formulas and rights of an author.
If a formula is shared, in open forum, or as a public download, and I use it to modify and create images, for sale, are these mentioned formulas royalty free? As an image creator and photographer, who normally builds images off original photos, I don't have to worry about this but in this case I just wanted to be sure I was following proper protocol.
Thanks

The formulas in the UF database are royalty free. If you sell your work, you do not need to pay or credit the formula author. its a great resource!

To be precise: you can freely create and sell images made with these formulas. However, they are not 100% "public domain": you can't sell the formulas themselves or derivative formulas. Here's some more information: https://www.ultrafractal.com/help/fractalwindows/copyrightandtweaking.html

Thank you for your replies, appreciate the clarity.