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Search: id:A031700
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| A031700 |
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Least term in period of continued fraction for sqrt(n) is 22. |
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+0 2
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| 122, 486, 1092, 1940, 3030, 4362, 5936, 7752, 9810, 12110, 14652, 17436, 20462, 23730, 27240, 30992, 34986, 39222, 43700, 48420, 53382, 58586, 64032, 69720, 70248, 75650, 81822, 88236, 94892, 101790, 108930, 116312, 123936, 131802, 139910
(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=[A031700] 121*n.^2+n (122, 486, 1092,. ,.,); Y=[A010861] 20 (20, 20, 20,..,); X=[A157958] 242*n+1 (243, 485, 727, ,. .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 243^2-122 *22^2=1; 485^2-486*22^2=1; 727^2-1092*22^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 10 2009]
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FORMULA
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a(n)=121*n^2+n (n>0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 10 2009]
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CROSSREFS
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Cf. A157958, A010861 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 10 2009]
Sequence in context: A004925 A070955 A116216 this_sequence A092775 A031599 A131970
Adjacent sequences: A031697 A031698 A031699 this_sequence A031701 A031702 A031703
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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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