**No**, this sequence `a_n=ln(n)` is not an arithmetic one because the difference between the adjacent terms is not a constant. For example,

`a_2-a_1=ln2-ln1=ln2`

but

`a_3-a_2=ln3-ln2=ln(3/2)!=ln(2).`

**No**, this sequence `a_n=ln(n)` is not an arithmetic one because the difference between the adjacent terms is not a constant. For example,

`a_2-a_1=ln2-ln1=ln2`

but

`a_3-a_2=ln3-ln2=ln(3/2)!=ln(2).`