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A049249 Smallest nonnegative value taken on by 10x^2 - ny^2 for an infinite number of integer pairs (x, y). 0
1, 2, 7, 4, 5, 4, 3, 2, 1, 0, 10, 10, 3, 10, 10, 10, 7, 10, 10, 10, 6, 2, 10, 10, 10, 10, 7, 10, 10, 10, 1, 8, 7, 6, 5, 4, 3, 2, 1, 0, 10, 10, 10, 10, 10, 10, 10, 10, 6, 10, 10, 10, 10, 4, 10, 10, 10, 10, 10, 10, 6, 2, 10, 10, 10, 6, 10, 10, 10, 10, 1, 10, 10, 10, 10, 10, 10, 10, 1, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..80.

MATHEMATICA

p = 10; 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], Which[n == 64, z = 10; fz = $Aborted, True, 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, 80}] (* Jean-Fran├žois Alcover, Oct 11 2016 *)

CROSSREFS

Sequence in context: A323755 A093590 A065629 * A222237 A325644 A198036

Adjacent sequences:  A049246 A049247 A049248 * A049250 A049251 A049252

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified June 6 18:59 EDT 2020. Contains 334832 sequences. (Running on oeis4.)