OFFSET
1,1
REFERENCES
H. C. Williams, Eisenstein's problem and continued fractions, Utilitas Math. 37 (1990) 145-157.
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..1000
F. Arndt, Beiträge zur Theorie der quadratischen Formen, Archiv der Mathematik und Physik 15 (1850) 467-478.
A. Cayley, Note sur l'équation x^2 - D*y^2 = +-4, D=5 (mod 8), J. Reine Angew. Math. 53 (1857) 369-371.
Steven R. Finch, Class number theory
Steven R. Finch, Class number theory [Cached copy, with permission of the author]
Eric Weisstein's World of Mathematics, Fundamental unit
MATHEMATICA
Select[ Range[2, 127], (fu = NumberFieldFundamentalUnits @ Sqrt[#]; SquareFreeQ[#] && IntegerQ[fu[[1, 2, 1]] ] && IntegerQ[fu[[1, 2, 2]] ]) &] (* Jean-François Alcover, Jun 20 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Steven Finch, Jun 13 2005
STATUS
approved