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Search: id:A116434
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| A116434 |
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Consider the array T(r,c) where is the number of r-almost primes less than or equal to r^c, starting with a(0)=1. This is the main diagonal. |
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+0
2
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| 0, 1, 3, 13, 90, 726, 7089, 78369, 973404, 13377156, 201443165, 3297443264
(list; graph; listen)
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OFFSET
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1,3
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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
Do[ Print@ AlmostPrimePi[n, (n + 1)^n], {n, 11}]
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CROSSREFS
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Cf. A116433, A116435.
Sequence in context: A002725 A097711 A114477 this_sequence A034513 A098462 A006898
Adjacent sequences: A116431 A116432 A116433 this_sequence A116435 A116436 A116437
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KEYWORD
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hard,more,nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 15 2006
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