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A013731
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a(n) = 2^(3*n+2).
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9
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4, 32, 256, 2048, 16384, 131072, 1048576, 8388608, 67108864, 536870912, 4294967296, 34359738368, 274877906944, 2199023255552, 17592186044416, 140737488355328, 1125899906842624, 9007199254740992, 72057594037927936, 576460752303423488
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OFFSET
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0,1
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COMMENTS
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Starting rank of the (j-1)-Washtenaw series for the fixed ratio 2^(-j-1) (see Griess). - J. Taylor (jt_cpp(AT)yahoo.com), Apr 03 2004
Independence number of the (n+1)-Sierpinski carpet graph. - Eric W. Weisstein, Sep 06 2017
Clique covering number of the (n+1)-Sierpinski carpet graph. - Eric W. Weisstein, Apr 22 2019
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LINKS
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FORMULA
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a(n) = 8*a(n-1), n > 0; a(0)=4.
G.f.: 4/(1-8x). (End)
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MAPLE
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MATHEMATICA
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Table[2^(3 n + 2), {n, 0, 20}]
2^(3 Range[0, 20] + 2)
LinearRecurrence[{8}, {4}, 20]
CoefficientList[Series[-(4/(-1 + 8 x)), {x, 0, 20}], x]
(* End *)
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PROG
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(Sage) [lucas_number1(3*n, 2, 0) for n in range(1, 20)] # Zerinvary Lajos, Oct 27 2009
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CROSSREFS
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Cf. A092811 (same sequence with 1 prepended).
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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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