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A164640
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a(n) = 8*a(n-2) for n > 2; a(1) = 1, a(2) = 6.
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7
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1, 6, 8, 48, 64, 384, 512, 3072, 4096, 24576, 32768, 196608, 262144, 1572864, 2097152, 12582912, 16777216, 100663296, 134217728, 805306368, 1073741824, 6442450944, 8589934592, 51539607552, 68719476736, 412316860416
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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a(n) = (7-(-1)^n)*2^(1/4*(6*n -15+3*(-1)^n)).
G.f.: x*(1+6*x)/(1-8*x^2).
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MATHEMATICA
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LinearRecurrence[{0, 8}, {1, 6}, 40] (* Harvey P. Dale, Nov 06 2013 *)
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PROG
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(Magma) [ n le 2 select 5*n-4 else 8*Self(n-2): n in [1..26] ];
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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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EXTENSIONS
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STATUS
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approved
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