

A049263


Smallest nonnegative value taken on by n*x^2  4*y^2 for an infinite number of integer pairs (x, y).


0



0, 2, 3, 0, 1, 2, 3, 4, 0, 4, 7, 8, 1, 10, 11, 0, 1, 2, 3, 4, 5, 2, 7, 8, 0, 4, 8, 12, 1, 14, 3, 16, 17, 18, 19, 0, 1, 2, 3, 4, 1, 6, 3, 8, 5, 10, 11, 12, 0, 4, 8, 4, 1, 2, 11, 20, 12, 4, 8, 24, 1, 26, 27, 0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 4, 11, 8, 13, 14, 15, 16, 0, 4, 8, 12, 1, 2, 23, 8, 1, 26, 3
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..91.


MATHEMATICA

p = 4; 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, 91}] (* JeanFrançois Alcover, Oct 11 2016 *)


CROSSREFS

Sequence in context: A309954 A124757 A242305 * A014588 A293497 A278164
Adjacent sequences: A049260 A049261 A049262 * A049264 A049265 A049266


KEYWORD

nonn


AUTHOR

David W. Wilson


STATUS

approved



