Respuesta :

LammettHash
[tex]a_{n+1}=a_n+4[/tex]
[tex]a_{n+1}=(a_{n-1}+4)+4=a_{n-1}+2\times4[/tex]
[tex]a_{n+1}=(a_{n-2}+4)+2\times4=a_{n-2}+3\times4[/tex]

and so on, until you're left with

[tex]a_{n+1}=a_1+4n=4n+13[/tex]