A103844 Least k such that n*(k^2)+n*k+1 is a square, or 0 if n is a square.

0, 3, 7, 0, 8, 4, 15, 2, 0, 3, 39, 1, 7, 3, 7, 0, 8, 4, 8, 2, 15, 4, 335, 1, 0, 15, 415, 2, 32, 3, 55, 5, 7, 11, 23, 0, 24, 12, 8, 1, 704, 4, 39, 3, 56, 1631, 2, 0, 35, 1799, 3, 87, 7, 32, 5, 55, 7, 15, 1, 15, 23, 47, 0, 48, 24, 16, 12, 16, 3, 9235919, 6, 119, 8, 519, 4, 135, 20, 4959, 3

Offset

1,2

Links

Table of n, a(n) for n=1..79.

Mathematica

ks[n_]:=Module[{k=1}, If[IntegerQ[Sqrt[n]], 0, While[!IntegerQ[ Sqrt[ n*k^2+n*k+1]], k++]; k]]; Array[ks, 80] (* Harvey P. Dale, Jul 18 2013 *)

Crossrefs

Sequence in context: A134976 A192044 A010622 * A199068 A198490 A354797

Adjacent sequences: A103841 A103842 A103843 * A103845 A103846 A103847

Keyword

nonn

Author

Pierre CAMI, Mar 30 2005

Status

approved