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A120134
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a(n) = 4 + floor(Sum_{k=1..n-1} a(k) / 2).
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13
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4, 6, 9, 13, 20, 30, 45, 67, 101, 151, 227, 340, 510, 765, 1148, 1722, 2583, 3874, 5811, 8717, 13075, 19613, 29419, 44129, 66193, 99290, 148935, 223402, 335103, 502655, 753982, 1130973, 1696460, 2544690, 3817035, 5725552, 8588328, 12882492
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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) ~ c * (3/2)^n, where c = 3.9320886310283094862025842648411406926537121258867950257873967568454133192... - Vaclav Kotesovec, May 07 2023
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MAPLE
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a := proc(n) option remember; 4 + iquo(add(a(k), k = 1..n-1), 2) end:
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MATHEMATICA
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f[s_]:= Append[s, 4+Floor[Plus @@ s/2]]; Nest[f, {4}, 37] (* Robert G. Wilson v, Jun 10 2006 *)
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PROG
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(SageMath)
@CachedFunction
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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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