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Search: id:A157443
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| A157443 |
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a(n)=121*n^2-38*n+3 (n>0) |
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+0
3
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| 86, 411, 978, 1787, 2838, 4131, 5666, 7443, 9462, 11723, 14226, 16971, 19958, 23187, 26658, 30371, 34326, 38523, 42962, 47643, 52566, 57731, 63138, 68787, 74678, 80811, 87186, 93803, 100662, 107763, 115106, 122691, 130518, 138587, 146898
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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If A=[A157443] 121*n.^2-38*n +3 (86,411,978,1787,.,); Y=[A157444] 1331*n-209 (1122, 2453,3784..,); X=[A157445] 14641*n^2-4598*n+362 (10405,49730,118337,.,) ; , we have for all terms, Pell's equation X^2-A*Y^2=1. Example: 10405^2-86*1122^2=1; 49730^2-411*2453^2=1; 118337^2-978*3784^2=1.
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LINKS
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Wolfram MathWorld, Pell Equation
Vincenzo Librandi, X^2-AY^2=1
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FORMULA
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a(n)=121*n^2-38*n+3 (n>0)
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EXAMPLE
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For n=1, a(1)=86; n=2, a(2)=411; n=3, a(3)=978
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CROSSREFS
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Cf. A157444, A157445
Sequence in context: A113690 A043379 A162028 this_sequence A035136 A128957 A034277
Adjacent sequences: A157440 A157441 A157442 this_sequence A157444 A157445 A157446
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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 01 2009
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