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Search: id:A114125
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| A114125 |
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a(n) = 10^n-th semiprime. |
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+0
6
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| 4, 26, 314, 3595, 40882, 459577, 5109839, 56168169, 611720495, 6609454805, 70937808071, 757060825018, 8040423200947, 85037651263063
(list; graph; listen)
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OFFSET
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0,1
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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MATHEMATICA
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fQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; c = 0; k = 2; Do[While[c < 10^n, If[fQ@k, c++ ]; k++ ]; Print[k - 1], {n, 0, 8}]
(* checked by *) SemiPrimePi[n_] := Sum[ PrimePi[n/Prime@i] - i + 1, {i, PrimePi@ Sqrt@n}]
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CROSSREFS
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Cf. A006880, A006988, A066265, A078972.
Sequence in context: A054592 A102202 A136503 this_sequence A063182 A167147 A132488
Adjacent sequences: A114122 A114123 A114124 this_sequence A114126 A114127 A114128
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 11 2006
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