What formula yields prime numbers?

x^2 - x + 41 =

these are for 5, 7, 10... after 40 they become composite with this equation

5^2 - 5 + 41 = 61 (Prime)

7^2 - 7 + 41 = 83 (Prime)

10^2 - 10 + 41 = 131 (Prime)