Monomorph
An integer which is expressible in only one way in the form x^2+Dy^2 or x^2-Dy^2 where x^2 is relatively prime to Dy^2. If the integer is expressible in more than one way, it is called a polymorph.
See also
Antimorph, Idoneal Number, Monomorphism, Pell Equation, PolymorphExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Monomorph." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Monomorph.html