In mathematics, Brewer sums are finite character sum introduced by Brewer (1961, 1966) related to Jacobsthal sums.

The Brewer sum is given by

where D_n is the Dickson polynomial (or "Brewer polynomial") given by

and () is the Legendre symbol.

The Brewer sum is zero when n is coprime to q²−1.

• Brewer, B. W. (1961), "On certain character sums", Transactions of the American Mathematical Society, 99 (2): 241–245, doi:10.2307/1993392, ISSN 0002-9947, JSTOR 1993392, MR 0120202, Zbl 0103.03205
• Brewer, B. W. (1966), "On primes of the form u²+5v²", Proceedings of the American Mathematical Society, 17 (2): 502–509, doi:10.2307/2035200, ISSN 0002-9939, JSTOR 2035200, MR 0188171, Zbl 0147.29801
• Berndt, Bruce C.; Evans, Ronald J. (1979), "Sums of Gauss, Eisenstein, Jacobi, Jacobsthal, and Brewer", Illinois Journal of Mathematics, 23 (3): 374–437, doi:10.1215/ijm/1256048104, ISSN 0019-2082, MR 0537798, Zbl 0393.12029
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