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Search: id:A013708
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| 3, 27, 243, 2187, 19683, 177147, 1594323, 14348907, 129140163, 1162261467, 10460353203, 94143178827, 847288609443, 7625597484987, 68630377364883, 617673396283947, 5559060566555523, 50031545098999707
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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1/3 + 1/27 + 1/243 +... = 3/8 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 29 2008]
Number n such that if a=n, b=8n, c=15n, d=36n*sqrt(3n), then a^3+b^3+c^3=d^2; example: a=3, b=24, c=45, d=324, 3^3+24^3+45^3=324^2 [From Vincenzo Librandi (vincenzo.librandi(AT)tn.it), Jan 23 2009]
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LINKS
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Tanya Khovanova, Recursive Sequences
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FORMULA
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a(n)=9*a(n-1), n>0 ; a(0)=3 . G.f.: 3/(1-9x). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 23 2008]
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CROSSREFS
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Sequence in context: A083713 A065100 A035088 this_sequence A102518 A074117 A037763
Adjacent sequences: A013705 A013706 A013707 this_sequence A013709 A013710 A013711
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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