Using elementary methods, we count the quadratic residues of a prime number of the form $ p = 4n-1 $ in a manner that has not been explored before. The simplicity of the pattern found leads to a novel formula for the class number $ h $ of the imaginary quadratic field $ \mathbb Q(\sqrt{-p}). $ Such formula is computable and does not rely on the Dirichlet character or the Kronecker symbol at all. Examples are provided and formulas for the sum of the quadratic residues are also found.
Citation: Jorge Garcia Villeda. A computable formula for the class number of the imaginary quadratic field $ \mathbb Q(\sqrt{-p}), \ p = 4n-1 $[J]. Electronic Research Archive, 2021, 29(6): 3853-3865. doi: 10.3934/era.2021065
Using elementary methods, we count the quadratic residues of a prime number of the form $ p = 4n-1 $ in a manner that has not been explored before. The simplicity of the pattern found leads to a novel formula for the class number $ h $ of the imaginary quadratic field $ \mathbb Q(\sqrt{-p}). $ Such formula is computable and does not rely on the Dirichlet character or the Kronecker symbol at all. Examples are provided and formulas for the sum of the quadratic residues are also found.
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