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A166465
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a(n) = 3*a(n-2) for n > 2; a(1) = 1, a(2) = 5.
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1
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1, 5, 3, 15, 9, 45, 27, 135, 81, 405, 243, 1215, 729, 3645, 2187, 10935, 6561, 32805, 19683, 98415, 59049, 295245, 177147, 885735, 531441, 2657205, 1594323, 7971615, 4782969, 23914845, 14348907, 71744535, 43046721, 215233605, 129140163
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OFFSET
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1,2
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COMMENTS
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Second binomial transform is A054485. Fifth binomial transform is A153596.
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LINKS
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FORMULA
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a(n) = (4+(-1)^n)*3^(1/4*(2*n-5+(-1)^n)).
G.f.: x*(1+5*x)/(1-3*x^2).
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PROG
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(Magma) [ n le 2 select 4*n-3 else 3*Self(n-2): n in [1..35] ];
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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