Red, ^{55 49} 45 bytes

func[n][x: 2 if n[loop n[x: x * x - x + 1]]x] 

Try it online!

• -6 thanks to Galen Ivanov
• -4 thanks to Pedro Maimere

This is the first real thing I wrote in Red. You have been warned.

Red, ^{55 49 45} 39 bytes

func[n][x: 2 loop n[x: x * x - x + 1]x] 

Try it online!

• -6 thanks to Galen Ivanov
• -4 thanks to Pedro Maimere
• -6 thanks to 9214

This is the first real thing I wrote in Red. You have been warned.

Red, 55 49 bytes

func[n][x: 2 if n > 0[loop n[x: x * x - x + 1]]x] 

Try it online!

-6 thanks to Galen Ivanov

This is the first real thing I wrote in Red. You have been warned.

Red, ^{55 49} 45 bytes

func[n][x: 2 if n[loop n[x: x * x - x + 1]]x] 

Try it online!

• -6 thanks to Galen Ivanov
• -4 thanks to Pedro Maimere

This is the first real thing I wrote in Red. You have been warned.

Red, 55 49 bytes

func[n][x: 2 either n > 0[loop n[x: x * x - x + 1]][x]] 

Try it online!

-6 thanks to Galen Ivanov

This is the first real thing I wrote in Red. You have been warned.

Red, 55 49 bytes

func[n][x: 2 if n > 0[loop n[x: x * x - x + 1]]x] 

Try it online!

-6 thanks to Galen Ivanov

This is the first real thing I wrote in Red. You have been warned.