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Search: id:A061229
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| A061229 |
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Floor of geometric mean of n and the reversal of n. |
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+0
3
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 3, 11, 15, 20, 23, 27, 31, 34, 38, 41, 6, 15, 22, 27, 31, 36, 40, 44, 47, 51, 9, 20, 27, 33, 38, 43, 47, 51, 56, 60, 12, 23, 31, 38, 44, 49, 54, 58, 63, 67, 15, 27, 36, 43, 49, 55, 60, 65, 70, 74, 18, 31, 40, 47, 54, 60, 66, 71, 76, 81, 22, 34, 44
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,2000
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FORMULA
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a(n) = floor[ {n * R(n)}^(1/2)], where R(n)= the digit reversal of n (A004086).
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EXAMPLE
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a(15)=floor(sqrt(15*51))=floor(sqrt(765))=27.
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PROGRAM
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(PARI) { default(realprecision, 100); for (n=1, 2000, x=n; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); write("b061229.txt", n, " ", floor(sqrt(n*r))) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 19 2009]
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CROSSREFS
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Cf. A079827.
Sequence in context: A028898 A081502 A079828 this_sequence A122666 A114288 A028899
Adjacent sequences: A061226 A061227 A061228 this_sequence A061230 A061231 A061232
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KEYWORD
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nonn,base
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 23 2001
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Jan 17 2009 at the suggestion of R. J. Mathar
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