ive been given a non linear difference equation y<t+1>= 3/16 + y<t>^2

dy<t+1> = 2y<t>
dy<t>

the two steady point when solved are 0.25 and 0.75

i need to construct a phase diagram, the table has been derived to help

y<t+1> 1/4 3/4 3/16 7/16 19/16

y<t> 1/4 3/4 0 1/2 1


In the table the first 2 terms are the steady points , does anyone know where the numbers 3/16, 7/16 and 19/16 originated from ?