0,1

If A=[A157998] 169*n.^2-n (168, 674, 1518,. ,.,); Y=[A010865] 26 (26, 26, 26,..,); X=[A157999] 338*n-1 (337, 675, 1013, ,. .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 337^2-168 *26^2=1; 675^2-674*26^2=1; 1013^2-1518*26^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 11 2009]

If A=[A158385] 676*n.^2+2*n (n>0, 678, 2708, 6090,.,); Y=[A010865] 26 (26, 26, 26, ,.,); X=[A158386] 676*n+1 (n>0, 677, 1353, 2029, .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 677^2-678*26^2=1; 1353^2-2708*26^2=1; 2029^2-6090*26^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 17 2009]

If A=[A158392] 676*n.^2-2*n (n>0, 674, 2700, 6078,.,); Y=[A010865] 26 (26, 26, 26, ,.,); X=[A158393] 676*n-1 (n>0, 675, 1351, 2027, .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 675^2-674*26^2=1; 1351^2-2700*26^2=1; 2027^2-6078*26^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tn.it), Mar 18 2009]

Tanya Khovanova, Recursive Sequences

Cf. A157998, A157999 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 11 2009]

Cf. A158385, A158386 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 17 2009]

Cf. A158392, A158393 [From Vincenzo Librandi (vincenzo.librandi(AT)tn.it), Mar 18 2009]

Sequence in context: A023468 A122163 A109341 this_sequence A031170 A003900 A040651

Adjacent sequences: A010862 A010863 A010864 this_sequence A010866 A010867 A010868

nonn

N. J. A. Sloane (njas(AT)research.att.com).