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A039700 Numbers n such that the largest power of 3 dividing n equals 3^omega(n). 2
1, 3, 18, 36, 45, 63, 72, 99, 117, 144, 153, 171, 207, 225, 261, 270, 279, 288, 333, 369, 378, 387, 423, 441, 477, 531, 540, 549, 576, 594, 603, 639, 657, 702, 711, 747, 756, 801, 873, 909, 918, 927, 945, 963, 981, 1017, 1026, 1080, 1089, 1125, 1143, 1152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

"Omega(n)" here means the number of prime factors of n counted without multiplicity. = Harvey P. Dale, Sep 30 2015

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

omega(18)=2 and 9=3^2 is the largest power of 3 dividing 18, hence 18 is in the sequence.

MATHEMATICA

Select[Range[1200], IntegerExponent[#, 3]==PrimeNu[#]&] (* Harvey P. Dale, Sep 30 2015 *)

CROSSREFS

Cf. A023534.

Sequence in context: A063116 A125284 A097989 * A069147 A094159 A138976

Adjacent sequences:  A039697 A039698 A039699 * A039701 A039702 A039703

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Sep 04 2002

STATUS

approved

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Last modified November 16 02:33 EST 2018. Contains 317252 sequences. (Running on oeis4.)