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Search: id:A157842
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| A157842 |
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a(n)=3600*n^2-5599*n+2177 (n>0) |
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+0
3
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| 178, 5379, 17780, 37381, 64182, 98183, 139384, 187785, 243386, 306187, 376188, 453389, 537790, 629391, 728192, 834193, 947394, 1067795, 1195396, 1330197, 1472198, 1621399, 1777800, 1941401, 2112202, 2290203, 2475404, 2667805
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OFFSET
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1,1
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COMMENT
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If A=[A157842] 3600*n.^2-5599*n +2177 (178, 5379, 17780,.,); Y=[A157843] 1728000*n - 1343760 (384240, 2112240..,); X=[A157844] 103680000*n^2-161251200*n +62697601 (5126401, 154915201,.,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 5126401^2-178 *384240^2=1; 154915201^2-5379*2112240^2=1.
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LINKS
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Edward Everett Withford, Pell Equation
Vincenzo Librandi, X^2-AY^2=1
Wolfram MathWorld, Pell Equation
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FORMULA
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a(n)=3600*n^2-5599*n+2177 (n>0)
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EXAMPLE
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For n=1, a(1)=178; n=2, a(2)5379; n=3, a(3)=17780
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CROSSREFS
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Cf. A157843, A157844
Sequence in context: A046436 A114081 A163730 this_sequence A053017 A140026 A108384
Adjacent sequences: A157839 A157840 A157841 this_sequence A157843 A157844 A157845
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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 07 2009
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