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Search: id:A007455
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| A007455 |
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Subsequences of [ 1,...,n ] in which each odd number has an even neighbor.
(Formerly M2480)
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+0
4
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| 1, 1, 3, 5, 11, 17, 39, 61, 139, 217, 495, 773, 1763, 2753, 6279, 9805, 22363, 34921, 79647, 124373, 283667, 442961, 1010295, 1577629, 3598219, 5618809, 12815247, 20011685, 45642179, 71272673, 162557031, 253841389, 578955451, 904069513
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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R. K. Guy, Moser, William O.J.: Numbers of subsequences without isolated odd members. Fibonacci Quarterly, 34, No. 2, 152-155 (1996).
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..400
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FORMULA
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a(n) = 3*a(n-2) + 2*a(n-4).
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CROSSREFS
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Cf. A007481, A007482, A007484.
Adjacent sequences: A007452 A007453 A007454 this_sequence A007456 A007457 A007458
Sequence in context: A006171 A060647 A125557 this_sequence A034729 A115786 A128550
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas, Mira Bernstein
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