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Search: id:A157786
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| A157786 |
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a(n)=27225*n^2-15248*n+2135 (n>0) |
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+0
3
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| 14112, 80539, 201416, 376743, 606520, 890747, 1229424, 1622551, 2070128, 2572155, 3128632, 3739559, 4404936, 5124763, 5899040, 6727767, 7610944, 8548571, 9540648, 10587175, 11688152, 12843579, 14053456, 15317783, 16636560
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OFFSET
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1,1
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COMMENT
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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.
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LINKS
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Edward Everett Withford, Pell Equation
Wolfram MathWorld, Pell Equation
Vincenzo Librandi, X^2-AY^2=1
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FORMULA
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a(n)=27225*n^2-15248*n+2135 (n>0)
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EXAMPLE
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For n=1, a(1)=14112; n=2, a(2)=80539; n=3, a(3)=201416;
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CROSSREFS
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Cf. A157787, A157788
Sequence in context: A066939 A140708 A066698 this_sequence A035918 A134610 A104825
Adjacent sequences: A157783 A157784 A157785 this_sequence A157787 A157788 A157789
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KEYWORD
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nonn
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AUTHOR
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Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 06 2009
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