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5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5, 1, 1, 1, 1, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (0,0,0,0,1)
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FORMULA
| a(n) = 1 + 4*[5|n], where [x|y] = 1 when x divides y, 0 otherwise.
a(n) = a(n-5).
Multiplicative with a(p^e, 5) = GCD(p^e, 5). David W. Wilson (davidwwilson(AT)comcast.net) Jun 12, 2005.
Dirichlet g.f. zeta(s)*(1+4/5^s). G.f. ( -5-x-x^2-x^3-x^4 ) / ( (x-1)*(1+x+x^2+x^3+x^4) ). - R. J. Mathar, Apr 04 2011
a(n)=4*floor(1/2*cos((2*n*Pi)/5)+1/2) + 1.
=4*floor(((n-1) mod 5)/4) + 1. [From Gary Detlefs, Dec 28 2011]
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CROSSREFS
| Cf. A109004.
Sequence in context: A188796 A161685 A129398 * A060904 A135469 A170817
Adjacent sequences: A109006 A109007 A109008 * A109010 A109011 A109012
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KEYWORD
| nonn,easy,mult
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AUTHOR
| Mitch Harris (Harris.Mitchell(AT)mgh.harvard.edu)
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