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 A049246 Smallest nonnegative value taken on by 7x^2 - ny^2 for an infinite number of integer pairs (x, y). 0
 3, 5, 1, 3, 2, 1, 0, 7, 7, 2, 7, 4, 2, 7, 3, 7, 7, 7, 1, 7, 7, 6, 5, 4, 3, 2, 1, 0, 7, 7, 1, 7, 7, 7, 7, 7, 3, 1, 7, 7, 7, 7, 3, 7, 7, 7, 1, 7, 7, 7, 3, 7, 7, 1, 7, 7, 6, 5, 1, 3, 2, 1, 0, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 4, 7, 7, 3, 7, 7, 7, 1, 7, 3, 7, 1, 7, 7, 7, 7, 7, 7, 1, 5, 7, 7, 7, 7, 3, 2, 6, 1, 7, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..105. MATHEMATICA p = 7; f[n_, z_] := FindInstance[x > 0 && y > 0 && p*x^2 - n*y^2 == z, {x, y}, Integers, 1]; a[n_] := For[z = 0, z <= p, z = z + GCD[n, p], Switch[n, 64 | 81, z = p; fz = \$Aborted, _, fz = TimeConstrained[f[n, z], 300]]; fz = If[fz === \$Aborted, {{x -> Null, y -> Null}}, fz]; If[fz =!= {}, Print["a(", n, ") = ", z, " {x, y} = ", {x, y} /. fz[[1]]]; Return[z]]]; Table[a[n], {n, 1, 105}] (* Jean-François Alcover, Oct 11 2016 *) CROSSREFS Sequence in context: A350882 A230407 A137759 * A231186 A021078 A130793 Adjacent sequences: A049243 A049244 A049245 * A049247 A049248 A049249 KEYWORD nonn AUTHOR David W. Wilson STATUS approved

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Last modified August 8 15:25 EDT 2024. Contains 375022 sequences. (Running on oeis4.)