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Search: id:A122756
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| A122756 |
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Odd indexed terms, a(n) = 2^n. Even indexed terms, a(n) = 2^n + 2^(n-1). |
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+0
3
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| 1, 2, 6, 8, 24, 32, 96, 128, 384, 512, 1536, 2048, 6144, 8192, 24576, 32768, 98304, 131072, 393216, 524288, 1572864, 2097152, 6291456, 8388608, 25165824, 33554432, 100663296, 134217728, 402653184, 536870912, 1610612736, 2147483648
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Row sums of triangle A133569. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 16 2007
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FORMULA
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a(n) =If[Mod[n, 2] == 0, 2^(n + 1), 2^n + 2^(n + 1)]=2*A084221[n]
a(0)=1, a(1)=2, a(2)=6, a(n)=4*a(n-2) for n>=3 . G.f.: (1+2*x+2*x^2)/(1-4*x^2) - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 14 2007
a(n)=-sqrt(2)*(1/2)^[(-1/2)*(-1)^(n-1)]*(-2)^(n-1)+2*2^(n-1)*sqrt(2)*(1/2)^[(-1/2)*(-1)^(n-1)]-(1/2)*[C(2*n,n) mod 2] [From Paolo P. Lava (ppl(AT)spl.at), Nov 19 2008]
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MATHEMATICA
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f[n_] := If[Mod[n, 2] == 0, 2^(n + 1), 2^n + 2^(n + 1)] Table[f[n], {n, 0, 30}]
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CROSSREFS
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Cf. A000079, A084221, A133569.
Sequence in context: A068496 A081957 A122758 this_sequence A116083 A115506 A057852
Adjacent sequences: A122753 A122754 A122755 this_sequence A122757 A122758 A122759
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KEYWORD
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nonn
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Sep 21 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 14 2007
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