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1, 5, 5, 9, 9, 13, 13, 17, 17, 21, 21, 25, 25, 29, 29, 33, 33, 37, 37, 41, 41, 45, 45, 49, 49, 53, 53, 57, 57, 61, 61, 65, 65, 69, 69, 73, 73, 77, 77, 81, 81, 85, 85, 89, 89, 93, 93, 97, 97, 101, 101, 105, 105, 109, 109, 113, 113, 117, 117, 121, 121, 125, 125, 129, 129, 133
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Index entries for sequences related to linear recurrences with constant coefficients, signature (1,1,-1).
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FORMULA
| a(n)=A005843(n)-(-1)^A001477(n)=2*A000027(n)+(-1)^A000027(n)=A005843(n)+A033999(n).
a(n)= a(n-1)+a(n-2)-a(n-3). G.f.: x*(1+4*x-x^2)/((1+x)*(x-1)^2). [R. J. Mathar, Aug 21 2009]
a(n)=4*n-a(n-1)-2 (with a(1)=1) [From Vincenzo Librandi, Nov 30 2010]
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PROG
| (PARI) a(n)=n+n+(-1)^n \\ Charles R Greathouse IV, Jun 09 2011
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CROSSREFS
| Cf. A000027, A004442, A005843, A033999.
Sequence in context: A200679 A124175 A168277 * A011986 A047880 A058491
Adjacent sequences: A163977 A163978 A163979 * A163981 A163982 A163983
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KEYWORD
| nonn,easy
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AUTHOR
| Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Aug 09 2009
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EXTENSIONS
| Link by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Mar 25 2010
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