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Search: id:A031434
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| A031434 |
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Least term in period of continued fraction for sqrt(n) is 10. |
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3
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| 26, 102, 228, 404, 630, 906, 1232, 1608, 2034, 2510, 3036, 3612, 3732, 4238, 4914, 5640, 6416, 7242, 8118, 9044, 10020, 11046, 11257, 12122, 13248, 14424, 15650, 16150, 16926, 18252, 19628, 21054, 22530, 24056, 25632, 27258, 28934
(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=[A031434] 25*n.^2+n (26,102,228,.,); Y=[A157510] 1000*n+20 (1020,2020,3020..,); X=[A157511] 5000*n^2+200*n+1 (5201,20401,45601,.,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 5201^2-26*1020^2=1; 20401^2-102*2020^2=1; 45601^2-228*3020^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 02 2009]
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LINKS
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Vincenzo Librandi, X^2-AY^2=1 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 02 2009]
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FORMULA
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a(n)=25*n^2+n (n>0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 02 2009]
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CROSSREFS
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Cf. A157510, A157511 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 02 2009]
Sequence in context: A026915 A136293 A065013 this_sequence A042320 A042322 A042324
Adjacent sequences: A031431 A031432 A031433 this_sequence A031435 A031436 A031437
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KEYWORD
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nonn
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AUTHOR
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David W. Wilson (davidwwilson(AT)comcast.net)
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