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Search: id:A057855
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| A057855 |
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Greatest k such that (kth prime) <= (n times n-th prime). |
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+0
1
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| 1, 3, 6, 9, 16, 21, 30, 36, 46, 61, 68, 86, 99, 110, 126, 146, 168, 184, 205, 223, 242, 270, 292, 321, 360, 381, 404, 429, 446, 477, 546, 574, 614, 637, 693, 717, 762, 804, 842, 890, 935, 965, 1029, 1059, 1105, 1134, 1222, 1304, 1348, 1381, 1423, 1483
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Might be roughly n^2/2 (seems to be marginally more at least for small n)
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EXAMPLE
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a(4)=9 since 4th prime is 7, 4*7=28, greatest prime less than or equal to 28 is 23 which is the 9th prime.
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MATHEMATICA
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a(n) = Pi[n.p(n)] Table[PrimePi[w*Prime[w]], {w, 1, 100}]
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CROSSREFS
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Cf. A020900, A020901, A020934-A020940.
Sequence in context: A112773 A070885 A002597 this_sequence A070120 A070126 A127644
Adjacent sequences: A057852 A057853 A057854 this_sequence A057856 A057857 A057858
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Nov 13 2000
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