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Series :

$$\sum_{i =1}^{n} i^k= 1^k+ 2^k + 3^k + 4^k +\ldots+n^k$$

where $k$ is a constant.

This does not seem to be Geometric progression , how can I evaluate the sum?

If possible if also want to find

$$\sum_{j =1}^{n} F(j)$$

where $F(j)$ is sum of the above series at $n=j$.

Aaron Maroja
  • 17,571

2 Answers2

2

Take a look at Faulhaber's formula to see that

$$\sum_{i=1}^{n} i^k = \frac{1}{k+1}\sum_{j=1}^{k}(-1)^j\binom{k+1}{j}B_jn^{k+1-j}$$

where $B_j$ are the Bernoulli numbers.

Aaron Maroja
  • 17,571
2

Alternately, look at the Bernoulli polynomials:
sums of the pth powers

GEdgar
  • 111,679