OFFSET
1,1
COMMENTS
This sequence is a subsequence of A087643.
EXAMPLE
35 belongs to this sequence because x^2 + 35*y^2 = 1 has the integer solution x=6, y=1.
MATHEMATICA
cr = {}; Do[If[IntegerQ[Sqrt[n]], , kk = NumberFieldFundamentalUnits[Sqrt[n]]; d1 = kk[[1]][[2]][[1]]; d2 = kk[[1]][[1]] kk[[1]][[2]][[2]]; d3 = Expand[(d1 + d2) (d1 - d2)]; If[d3 == 1, k1 = Max[Denominator[d1], Denominator[d2]]; If[k1 == 1, AppendTo[cr, n]]]], {n, 2, 100}]; cr
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Oct 10 2011
EXTENSIONS
Definition clarified by Emmanuel Vantieghem, Mar 06 2017
STATUS
approved