

A049264


Smallest nonnegative value taken on by n*x^2  5*y^2 for an infinite number of integer pairs (x, y).


0



1, 2, 3, 4, 0, 1, 2, 3, 1, 5, 6, 3, 5, 1, 10, 11, 3, 13, 14, 0, 1, 2, 2, 4, 5, 5, 7, 7, 5, 10, 11, 3, 7, 5, 15, 4, 5, 2, 19, 20, 9, 22, 23, 24, 0, 1, 2, 3, 1, 5, 6, 7, 3, 1, 10, 4, 3, 5, 6, 15, 16, 3, 7, 11, 5, 19, 22, 3, 1, 25, 11, 27, 5, 5, 30, 31, 7, 33, 34, 0, 1, 2, 3, 4, 5, 1, 7, 8, 5, 10, 11
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OFFSET

1,2


LINKS

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


MATHEMATICA

p = 5; 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: A197024 A031235 A090141 * A010874 A278182 A125926
Adjacent sequences: A049261 A049262 A049263 * A049265 A049266 A049267


KEYWORD

nonn


AUTHOR

David W. Wilson


STATUS

approved



