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A049265
Smallest nonnegative value taken on by n*x^2 - 6*y^2 for an infinite number of integer pairs (x, y).
0
1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 3, 6, 7, 2, 6, 10, 3, 12, 3, 14, 15, 16, 17, 0, 1, 2, 3, 4, 5, 6, 1, 8, 3, 10, 11, 12, 13, 2, 6, 10, 3, 18, 3, 12, 21, 10, 23, 24, 1, 26, 27, 28, 29, 0, 1, 2, 3, 4, 3, 6, 7, 2, 9, 10, 11, 12, 3, 12, 15, 16, 17, 18, 19, 2, 6, 10, 14, 6, 1, 26, 3, 12, 3, 30, 10, 2
OFFSET
1,2
MATHEMATICA
p = 6; f[n_, z_] := FindInstance[x > 0 && y > 0 && n*x^2 - p*y^2 == z, {x, y}, Integers, 1]; a[n_] := For[z = 0, True, z = z + GCD[n, p], 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, 86}] (* Jean-François Alcover, Oct 11 2016 *)
CROSSREFS
Sequence in context: A303534 A369183 A030567 * A010875 A260187 A257687
KEYWORD
nonn
AUTHOR
David W. Wilson, Dec 11 1999
STATUS
approved