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A158643
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a(n)=26*(26*n^2+1).
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1
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26, 702, 2730, 6110, 10842, 16926, 24362, 33150, 43290, 54782, 67626, 81822, 97370, 114270, 132522, 152126, 173082, 195390, 219050, 244062, 270426, 298142, 327210, 357630, 389402, 422526, 457002, 492830, 530010, 568542, 608426, 649662, 692250
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| The identity (52*n^2+1)^2 - (676*n^2+26) * (2*n)^2 = 1 can be written as
the Pell equation (A158644(n))^2 - a(n) * (A005843(n))^2 =1.
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LINKS
| Philippe Chevanne, Pell Equation
Vincenzo Librandi, X^2-AY^2=1
Edward Everett Withford, Pell Equation
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FORMULA
| a(n)= 3*a(n-1) -3*a(n-2) +a(n-3). G.f.: -26*(1+24*x+27*x^2)/(x-1)^3.
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MATHEMATICA
| 26(26Range[0, 40]^2+1) (* From Harvey P. Dale, Mar 30 2011 *)
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CROSSREFS
| Cf. A005843, A158644
Sequence in context: A041313 A042302 A097835 * A181227 A094738 A182612
Adjacent sequences: A158640 A158641 A158642 * A158644 A158645 A158646
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 23 2009
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EXTENSIONS
| Comment rephrased and redundant formula replaced by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 19 2009
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