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A066681 Badly sieved numbers (A066680) which are not primes. 2
8, 12, 18, 27, 30, 45, 50, 63, 70, 75, 80, 98, 105, 112, 125, 128, 147, 154, 165, 168, 175, 176, 182, 192, 195, 208, 220, 231, 242, 245, 260, 264, 273, 275, 286, 312, 325, 338, 340, 343, 357, 363, 374, 380, 385, 396, 399, 408 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences generated by sieves

FORMULA

A099104(a(n))*A005171(a(n)) = 1. [Reinhard Zumkeller, Nov 12 2009]

EXAMPLE

8 is the first nonprime in A066680, as multiples of 2 are marked only up to 4 = 2^2 and all other multiples of unmarked numbers < 8 do not hit 8.

PROG

(Haskell)

a066681 n = a066681_list !! (n-1)

a066681_list = filter ((== 0) . a010051) a066680_list

-- Reinhard Zumkeller, Feb 17 2012

CROSSREFS

Cf. A010051.

Sequence in context: A245989 A293529 A028393 * A276403 A171241 A120137

Adjacent sequences:  A066678 A066679 A066680 * A066682 A066683 A066684

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Dec 31 2001

STATUS

approved

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Last modified April 13 21:24 EDT 2021. Contains 342941 sequences. (Running on oeis4.)