# sum of the series

• Jun 6th 2010, 11:00 AM
poorna
sum of the series
Hey what is the sum of the series :

1 + (1 + 2)/2! + (1 + 2 + 2^2)/3! +.....

I know that the nth term is (2^n - 1)/n! .
How does that help?

Thanks :)
• Jun 6th 2010, 11:15 AM
mfetch22
numerical estimation
I'm thinking that this series is an expansion of a simpler function, but I'm not certain. Instead, since I couldnt see the pattern, I just numerically calculated it and heres roughly what I found to be the sum:

4.6707742704716
• Jun 6th 2010, 11:20 AM
Bruno J.
Recall that $\sum_{j=0}^\infty \frac{x^j}{j!} = e^x$...