In a rare 1631 work entitled Academiae Algebrae, J. Faulhaber published a number of formulae for power sums of the first positive
integers. A detailed analysis of Faulhaber's work may be found in Knuth (1993)
and, with a few amendments, in Knuth (2001).
Among the results presented by Faulhaber (without any indication of how they were derived) were the sums of odd powers
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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where .
While Faulhaber believed that analogous polynomials in
with alternating signs would continue to exist for all powers
,
a rigorous proof was first published by Jacobi (1834; Knuth 1993).
The case
is sometimes known as Nicomachus's theorem.
Expressing such sums directly in terms of for powers
, ..., 10 gives
(10)
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(11)
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(12)
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(13)
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(14)
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(15)
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(16)
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(17)
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(18)
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(19)
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While Faulhaber was not aware of (and did not discover) Bernoulli numbers or harmonic numbers, a general formula
for the sum of
for
from 1 to
can be given in closed form by
(20)
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(21)
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where
is a generalized harmonic number,
is the Kronecker delta,
is a binomial coefficient, and
is the
th Bernoulli number.
In his work, Faulhaber also considered and (correctly) claimed that the -fold summation of
,
, ...,
is a polynomial in
when
3, 5, .... Additional details are given by Knuth (1993,
2001).
Any of these power sums might be termed a "Faulhaber sum."