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Search: id:A116428
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| A116428 |
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The number of n-almost primes less than or equal to 8^n, starting with a(0)=1. |
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+0
8
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| 1, 4, 22, 125, 669, 3410, 16677, 78369, 359110, 1612613, 7133274, 31185350, 135062165, 580556958, 2480278767
(list; graph; listen)
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OFFSET
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0,2
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MATHEMATICA
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AlmostPrimePi[k_Integer, n_] := Module[{a, i}, a[0] = 1; If[k == 1, PrimePi[n], Sum[PrimePi[n/Times @@ Prime[ Array[a, k - 1]]] - a[k - 1] + 1, Evaluate[ Sequence @@ Table[{a[i], a[i - 1], PrimePi[(n/Times @@ Prime[Array[a, i - 1]])^(1/(k - i + 1))]}, {i, k - 1}]]]]]; Eric Weisstein (eww(AT)wolfram.com) Feb 07 2006
Table[ AlmostPrimePi[n, 8^n], {n, 14}]
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CROSSREFS
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Cf. A078840, A078841, A078842, A116432, A078843, A116426, A078844, A116427, A078845, A116428, A116429, A116430, A078846, A116431.
Sequence in context: A065983 A136777 A056625 this_sequence A121187 A011789 A047039
Adjacent sequences: A116425 A116426 A116427 this_sequence A116429 A116430 A116431
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KEYWORD
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more,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 14 2006
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