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A166450
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a(n) = 3*a(n-2) for n > 2; a(1) = 1, a(2) = 6.
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1
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1, 6, 3, 18, 9, 54, 27, 162, 81, 486, 243, 1458, 729, 4374, 2187, 13122, 6561, 39366, 19683, 118098, 59049, 354294, 177147, 1062882, 531441, 3188646, 1594323, 9565938, 4782969, 28697814, 14348907, 86093442, 43046721, 258280326
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OFFSET
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1,2
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COMMENTS
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Second binomial transform is A055845. Sixth binomial transform is A153597.
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LINKS
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FORMULA
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a(n) = (3+(-1)^n)*3^(1/4*(2*n-1+(-1)^n))/2.
G.f.: x*(1+6*x)/(1-3*x^2).
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MATHEMATICA
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LinearRecurrence[{0, 3}, {1, 6}, 50] (* G. C. Greubel, May 14 2016 *)
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PROG
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(Magma) [ n le 2 select 5*n-4 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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