1,1

If A=[A157786] 27225*n.^2-15248*n +2135 (14112, 80539, 201416,.,); Y=[A157787] 8984250*n -2515920 (6468330, 15452580,..,); X=[A157770] 1482401250*n^2-830253600*n +116250751 (768398401, 4385348551,.,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 768398401^2-14112 *6468330^2=1; 4385348551^2-80539*15452580^2=1.

Edward Everett Withford, Pell Equation

Vincenzo Librandi, X^2-AY^2=1

Philippe Chevanne, Pell Equation

a(n)=1482401250*n^2-830253600*n+116250751 (n>0)

For n=1, a(1)=768398401; n=2, a(2)=4385348551

Cf. A157786, A157787

Sequence in context: A068725 A104932 A118876 this_sequence A058420 A166121 A046186

Adjacent sequences: A157785 A157786 A157787 this_sequence A157789 A157790 A157791

nonn

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 06 2009