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Search: id:A083869
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| A083869 |
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a(1)=1 then a(n) is the least k>=1 such that the nested radical sqrt(a(1)^2+sqrt(a(2)^2+sqrt(a(3)^2+(....+sqrt(a(n)^2)))...) is an integer. |
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+0
6
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| 1, 3, 55, 43631, 99515655135, 4723258824886629604131775, 589359179694820074404152604620573424809709490316113791, 13331474848620898858862175943355927686887898121894707763190978243005066121710225\ 087713374054319814910927464555589375
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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n = sqrt(a(1)^2+sqrt(a(2)^2+sqrt(a(3)^2+(....+sqrt(a(n)^2)))...)
Equals main diagonal of triangle A166994. [From Paul D. Hanna (pauldhanna(AT)juno.com), Nov 18 2009]
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MAPLE
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k=55 is the least integer such that sqrt(1^2+sqrt(3^2+sqrt(k^2)))=3 is an integer hence a(3)=55.
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CROSSREFS
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Sequence in context: A002818 A119190 A110058 this_sequence A119188 A111451 A070731
Cf. A166994. [From Paul D. Hanna (pauldhanna(AT)juno.com), Nov 18 2009]
Adjacent sequences: A083866 A083867 A083868 this_sequence A083870 A083871 A083872
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KEYWORD
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nonn,new
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 18 2003
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