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A037489
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Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,1.
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1
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2, 9, 38, 153, 614, 2457, 9830, 39321, 157286, 629145, 2516582, 10066329, 40265318, 161061273, 644245094, 2576980377, 10307921510, 41231686041, 164926744166, 659706976665, 2638827906662, 10555311626649, 42221246506598
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = 4a(n-1) + a(n-2) - 4a(n-3).
G.f.: x*(2+x) / ( (x-1)*(4*x-1)*(1+x) ). - R. J. Mathar, Nov 21 2011
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MATHEMATICA
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PROG
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(Magma) I:=[2, 9, 38]; [n le 3 select I[n] else 4*Self(n-1)+Self(n-2)-4*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Jun 22 2012
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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