Question 961013
<pre>
d = 2nd term - 1st term = 4-9 = -5 = 3rd term - 2nd term = -1 - 4 = -5
{{{a[1]=matrix(1,4,first,term,""="",9)}}}
{{{a[n]=a[1]+(n-1)d}}}{{{""=""}}}{{{9+(n-1)(-5)=9-5(n-1)=9-5n+5=14-5n}}}

{{{a[n]=14-5n}}}

Edwin</pre>