Respuesta :
Answer:
[tex]\large \boxed{\sf \ \ 23 \ \ }[/tex]
Step-by-step explanation:
Hello, please consider the following.
[tex]a_1=f(1)=3\\\\a_2=f(1)+4=3+4=7\\\\a_3=f(3)=a_2+4=7+4=11\\\\a_4=a_3+4=11+4=15\\\\a_5=a_4+4=15+4=19\\\\a_6=a_5+4=19+4=23[/tex]
So the answer is 23.
Hope this helps.
Do not hesitate if you need further explanation.
Thank you