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A000955
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A sequence satisfying (a(2n+1) + 1)^3 = Sum_{k=1..2n+1} a(k)^3.
(Formerly M4073 N1688)
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2
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1, 6, 8, 262, 2448, 17997702, 44082372248, 5829766629386380698502, 256989942683351711945337288361248, 198131491921177194311506308094238133848780474484255622782351242502
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OFFSET
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1,2
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REFERENCES
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N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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a(1)=1, a(2)=6, a(3)=8, a(2n+2) = 3*a(2n+1)^2 + 8*a(2n+1) + 6, a(2n+3) = 3*a(2n+1)^3 + 12*a(2n+1)^2 + 17*a(2n+1) + 8. [Sean A. Irvine, Sep 16 2011]
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MATHEMATICA
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a[1] = 1; a[2] = 6; a[3] = 8; a[n_] := a[n] = If[EvenQ[n], 3*a[n-1]^2 + 8*a[n-1] + 6, 3*a[n-2]^3 + 12*a[n-2]^2 + 17*a[n-2] + 8]; Array[a, 10] (* Jean-François Alcover, Feb 15 2016, after Sean A. Irvine *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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