Question 856924
<pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
2-10+50-250...-a6
{{{a[n] = 2(-5)^(n-1)}}}
{{{a[5] = 2(-5)^(4) = 1250}}}
{{{a[6] = 2(-5)^(5) = -6250}}}