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A049269 Smallest nonnegative value taken on by nx^2 - 10y^2 for an infinite number of integer pairs (x, y). 0
1, 2, 2, 4, 5, 6, 2, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 2, 1, 10, 11, 12, 2, 6, 10, 10, 2, 2, 10, 20, 6, 22, 15, 6, 25, 26, 3, 28, 29, 0, 1, 2, 2, 4, 5, 4, 2, 8, 1, 10, 6, 10, 10, 14, 5, 14, 17, 10, 1, 20, 6, 22, 2, 6, 10, 14, 2, 10, 6, 30, 31, 8, 10, 10, 35, 4, 22, 38, 6, 40, 26, 18, 2, 44, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..85.

MATHEMATICA

f[n_, z_] := FindInstance[x>0 && y>0 && n*x^2 - 10*y^2 == z, {x, y}, Integers, 1]; a[n_] := For[z = 0, True, z = z + GCD[n, 10], fz = f[n, z]; If[fz =!= {}, Print["a(", n, ") = ", z, " {x, y} = ", {x, y} /. fz[[1]]]; Return[z]]]; Array[a, 85] (* Jean-Fran├žois Alcover, Oct 09 2016 *)

CROSSREFS

Sequence in context: A240851 A261665 A208096 * A085085 A121600 A126870

Adjacent sequences:  A049266 A049267 A049268 * A049270 A049271 A049272

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 3 04:39 EST 2016. Contains 278698 sequences.