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A057855 Greatest k such that (k-th prime) <= (n times n-th prime). 0
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; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Might be roughly n^2/2 (seems to be marginally more at least for small n)

EXAMPLE

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.

MATHEMATICA

a(n) = Pi[n.p(n)] Table[PrimePi[w*Prime[w]], {w, 1, 100}]

CROSSREFS

Cf. A020900, A020901, A020934-A020940.

Sequence in context: A112773 A070885 A002597 * A198685 A070120 A070126

Adjacent sequences:  A057852 A057853 A057854 * A057856 A057857 A057858

KEYWORD

nonn

AUTHOR

Henry Bottomley (se16(AT)btinternet.com), Nov 13 2000

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.