Search: id:A157998 Results 1-1 of 1 results found. %I A157998 %S A157998 168,674,1518,2700,4220,6078,8274,10808,13680,16890,20438,24324,28548, %T A157998 33110,38010,43248,48824,54738,60990,67580,74508,81774,89378,97320, %U A157998 105600,114218,123174,132468,142100,152070,162378,173024,184008,195330 %N A157998 a(n)=169*n^2-n (n>0) %C A157998 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. %H A157998 Edward Everett Withford, Pell Equation %H A157998 Vincenzo Librandi, X^2-AY^2=1 %H A157998 Wolfram MathWorld, Pell Equation %F A157998 a(n)=169*n^2-n (n>0) %e A157998 For n=1, a(1)=168; n=2, a(2)=674; n=3, a(3)=1518 %Y A157998 Cf. A010865, A157999 %Y A157998 Sequence in context: A158219 A027679 A137863 this_sequence A110285 A070835 A112551 %Y A157998 Adjacent sequences: A157995 A157996 A157997 this_sequence A157999 A158000 A158001 %K A157998 nonn %O A157998 1,1 %A A157998 Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 11 2009 Search completed in 0.001 seconds