Recommend a dynamically generated hexcolor, based on any text string, that is legible on white background

 a4a947
 b9c31d
 ce80da
 866cfe
 29b80b

 a4a947
 b9c31d
 ce80da
 866cfe
 29b80b

a4a947 -> 157
b9c31d -> 174
ce80da -> 161
866cfe -> 132
29b80b -> 122

recommended: 866cfe (luminosity below 150)
866cfe