Respuesta :

Answer:

  68

Step-by-step explanation:

[tex]a_2=2a_1+4=2\cdot 5+4=14\\\\a_3=2a_2+4=2\cdot 14+4=32\\\\a_4=2\cdot 32+4=68[/tex]

  a₄ = 68

_____

The explicit formula is

  an = 9·2^(n-1) -4