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A156639 a(n)=169*n^2-140*n+29 +0
7
29, 58, 425, 1130, 2173, 3554, 5273, 7330, 9725, 12458, 15529, 18938, 22685, 26770, 31193, 35954, 41053, 46490, 52265, 58378, 64829, 71618, 78745, 86210, 94013, 102154, 110633, 119450, 128605, 138098, 147929, 158098 (list; graph; listen)
OFFSET

1,1

COMMENT

Arises in solving Pell equations of the form X^2 - A*Y^2 = 1.

Let n=[A156718] (70,99,239,268,408,437,...,). If A=[A156640] (29,338,985,...,) or A=[156639] (29,58,425) =(n^2+1)/13^2 , Y=26*n, [A156636] (1820,6214,10608,...,) or Y=[A156627] (2574,6968,11362,...,) and X=2*n^2+1 [A156721] (9801,19603,143649,...,) or X=[A156735] (9801,114243,332929,...,) , we have for all terms, Pell's equation X^2-A*Y^2=1. Example: For n=70, A=29, Y=1820, X=9801; 9801^2-29*1820^2=1; n=99, A=58, Y=2574, X=19603; 19603^2-58*2574^2=1; n=239, A=338, Y=6214, X=114243; 114243^2-338*6214^2=1; n=268, A=425, Y=6968, X=143649; 143649^2-425*6968^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 20 2009]

LINKS

Vincenzo Librandi, X^2-AY^2=1 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 20 2009]

EXAMPLE

For n=0, a(0)=29; n=1, a(1)=58; n=2, a(2)=425

CROSSREFS

Cf. A156640

Cf. A156718, A156636, A156627, A156721, A156735 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 20 2009]

Sequence in context: A004922 A004942 A033904 this_sequence A080170 A078848 A055784

Adjacent sequences: A156636 A156637 A156638 this_sequence A156640 A156641 A156642

KEYWORD

nonn

AUTHOR

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 15 2009

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.


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