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A065334 2-exponents to represent 3-smooth numbers (A065332). 3
0, 1, 0, 2, 0, 1, 0, 3, 0, 0, 0, 2, 0, 0, 0, 4, 0, 1, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

For k > 0 with A065332(k) > 0: A065332(k) = (2^a(k)) * (3^A065335(k)).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..100000

FORMULA

a(n) = A007814(n) * A065333(n).

MATHEMATICA

a[n_] := If[n/2^(e = IntegerExponent[n, 2])/3^IntegerExponent[n, 3] == 1, e, 0]; Array[a, 100] (* Amiram Eldar, Feb 21 2021 *)

PROG

(PARI) A065334(n) = if(1==n, 0, my(f = factor(n)); if(f[#f~, 1] > 3, 0, valuation(n, 2))); \\ Antti Karttunen, Oct 09 2018

CROSSREFS

Cf. A007814, A065332, A065333, A065335.

Sequence in context: A103775 A331594 A093057 * A162590 A276424 A191258

Adjacent sequences:  A065331 A065332 A065333 * A065335 A065336 A065337

KEYWORD

nonn,look

AUTHOR

Reinhard Zumkeller, Oct 29 2001

EXTENSIONS

Typo in formula corrected, erroneous comment removed by Antti Karttunen, Oct 09 2018

STATUS

approved

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Last modified April 14 06:30 EDT 2021. Contains 342946 sequences. (Running on oeis4.)