

A049247


Smallest nonnegative value taken on by 8x^2  ny^2 for an infinite number of integer pairs (x, y).


0



4, 0, 5, 4, 3, 2, 1, 0, 8, 8, 8, 8, 8, 2, 8, 8, 4, 0, 8, 8, 8, 2, 1, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 8, 8, 8, 8, 2, 8, 8, 8, 8, 5, 8, 8, 2, 1, 8, 4, 0, 8, 8, 3, 2, 8, 8, 8, 8, 8, 8, 8, 2, 8, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 8, 8, 8, 8, 8, 1, 8, 8, 8, 5, 8, 8, 2, 8, 8, 8, 8, 8, 4, 8, 2, 8, 8, 4, 0, 8, 8, 3, 2, 1, 8, 8
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Table of n, a(n) for n=1..105.


MATHEMATICA

p = 8; 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 == 49, z = 4; fz = $Aborted, n == 81, z = 8; fz = $Aborted, n == 83, z = 5; fz = $Aborted, n == 101, z = 3; 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, 105}] (* JeanFrançois Alcover, Oct 11 2016 *)


CROSSREFS

Sequence in context: A201196 A019906 A197251 * A175621 A016578 A268631
Adjacent sequences: A049244 A049245 A049246 * A049248 A049249 A049250


KEYWORD

nonn


AUTHOR

David W. Wilson


STATUS

approved



