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Search: id:A158593
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| 1, 39, 153, 343, 609, 951, 1369, 1863, 2433, 3079, 3801, 4599, 5473, 6423, 7449, 8551, 9729, 10983, 12313, 13719, 15201, 16759, 18393, 20103, 21889, 23751, 25689, 27703, 29793, 31959, 34201, 36519, 38913, 41383, 43929, 46551, 49249, 52023, 54873
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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The identity (38*n^2+1)^2 - (361*n^2+19)*(2*n)^2 = 1 can be written in
Pell-format as (a(n))^2 - A158592(n)* (A005843(n))^2 =1.
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LINKS
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Vincenzo Librandi, X^2-AY^2=1
Edward Everett Withford, Pell Equation
Wolfram MathWorld, Pell Equation
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FORMULA
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a(n)= 3*a(n-1) -3*a(n-2) +a(n-3). G.f.: -(1+36*x+39*x^2)/(x-1)^3.
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CROSSREFS
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Cf. A005843, A158592
Sequence in context: A044752 A072253 A128826 this_sequence A158598 A105838 A124619
Adjacent sequences: A158590 A158591 A158592 this_sequence A158594 A158595 A158596
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KEYWORD
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nonn,easy,new
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AUTHOR
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Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 22 2009
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EXTENSIONS
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Comment rewritten, formula replaced by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 28 2009
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