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Search: id:A109848
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| A109848 |
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Highest common factor of n and its 9's complement. |
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+0
2
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| 1, 1, 3, 1, 1, 3, 1, 1, 9, 1, 11, 3, 1, 1, 3, 1, 1, 9, 1, 1, 3, 11, 1, 3, 1, 1, 9, 1, 1, 3, 1, 1, 33, 1, 1, 9, 1, 1, 3, 1, 1, 3, 1, 11, 9, 1, 1, 3, 1, 1, 3, 1, 1, 9, 11, 1, 3, 1, 1, 3, 1, 1, 9, 1, 1, 33, 1, 1, 3, 1, 1, 9, 1, 1, 3, 1, 11, 3, 1, 1, 9, 1, 1, 3, 1, 1, 3, 11, 1, 9, 1, 1, 3, 1, 1, 3, 1, 1, 99, 1, 1, 3
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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a(55)=11 because 9-complement of 55 is 99-55=44 and the greatest common divisor of 44 and 55 is 11.
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MAPLE
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digs := proc(inp::integer) local resul, shiftinp : resul := 1 : shiftinp := iquo(inp, 10) : while shiftinp > 0 do resul := resul+1 : shiftinp := iquo(shiftinp, 10) : od : RETURN(resul) : end: nin := proc(inp::integer) RETURN(10^digs(inp)-1-inp) : end : for n from 1 to 80 do comp := nin(n) ; #print(n, comp, gcd(n, comp)) ; printf("%d, ", gcd(n, comp)) ; od : - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 27 2006
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CROSSREFS
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Cf. A109847, A084021.
Sequence in context: A038500 A091840 A083985 this_sequence A104146 A133705 A046111
Adjacent sequences: A109845 A109846 A109847 this_sequence A109849 A109850 A109851
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KEYWORD
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base,easy,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jul 06 2005
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 27 2006
More terms from Joshua Zucker (joshua.zucker(AT)stanfordalumni.org), May 03 2006
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