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Need some help

Name: Anonymous 2007-10-16 22:30

Need an expression for Sn where
Sn = a1 + a2 + a3 + ... + an
and
an = n(n+1)

Name: Anonymous 2007-10-16 22:44

n*(n+1)(2n+1)/6 + n(n+1)/2

Name: Anonymous 2007-10-16 22:52

Appears to work, thanks. How did you figure it out?

Name: Anonymous 2007-10-16 22:53

It turns into the sum from i=1 to n of n^2 + n

The sum from i = 1 to n of n^2 is n*(n+1)(2n+1)/6
The sum from i = 1 to n of n is n(n+1)/2

Google summation formulas for a list of formulas for the sum from i = 1 to n of n^a

Name: Anonymous 2007-10-16 22:56

Thank you.

Name: Anonymous 2007-10-16 22:57

No problem

Name: Anonymous 2007-10-17 0:40

Kind Anonymous? In MY /sci/?

OP: gb2/high_school/, at your age I was doing HUGE infinite series that even Ramanujan couldn't comphrend.

Name: Anonymous 2007-10-17 22:42

FAULHABER'S FORMULA

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