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A056913
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Odd squarefree numbers for which the number of prime divisors is even.
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8
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1, 15, 21, 33, 35, 39, 51, 55, 57, 65, 69, 77, 85, 87, 91, 93, 95, 111, 115, 119, 123, 129, 133, 141, 143, 145, 155, 159, 161, 177, 183, 185, 187, 201, 203, 205, 209, 213, 215, 217, 219, 221, 235, 237, 247, 249, 253, 259, 265, 267, 287, 291, 295, 299, 301, 303
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Liouville function lambda(n) (A008836) is positive.
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REFERENCES
| H. Gupta, A formula for L(n), J. Indian Math. Soc., 7 (1943), 68-71.
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MATHEMATICA
| f[n_]:=Last/@FactorInteger[n]=={1, 1}&&FactorInteger[n][[1, 1]]>2; a=6; lst={1}; Do[If[f[n], AppendTo[lst, n]], {n, 6!}]; lst (* From Vladimir Orlovsky, Nov 23 2009 *)
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CROSSREFS
| Cf. A056911, A056912, A008836, A026424, A028260.
Sequence in context: A098905 A024556 A146166 * A002557 A128907 A020162
Adjacent sequences: A056910 A056911 A056912 * A056914 A056915 A056916
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KEYWORD
| easy,nonn
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AUTHOR
| James A. Sellers (sellersj(AT)math.psu.edu), Jul 07 2000
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