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A182908
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Rank of 2^n when all prime powers (A246655) p^n, for n>=1, are jointly ranked.
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6
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1, 3, 6, 10, 18, 27, 44, 70, 117, 198, 340, 604, 1078, 1961, 3590, 6635, 12370, 23150, 43579, 82267, 155921, 296347, 564688, 1078555, 2064589, 3958999, 7605134, 14632960, 28195586, 54403835, 105102701, 203287169, 393625231, 762951922
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(3)=6 because 2^3 has rank 6 in the sequence (2,3,4,5,7,8,9,...).
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MATHEMATICA
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T[i_, j_]:=Sum[Floor[j*Log[Prime[i]]/Log[Prime[h]]], {h, 1, PrimePi[Prime[i]^j]}]; Flatten[Table[T[i, j], {i, 1, 1}, {j, 1, 22}]]
f[n_] := Sum[ PrimePi[ Floor[2^(n/k)]], {k, n + 1}]; Array[f, 34] (* Robert G. Wilson v, Jul 08 2011 *)
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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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