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A134361 a(n) = smallest integer >= n which has only prime factors 2 and 3. 4
1, 2, 3, 4, 6, 6, 8, 8, 9, 12, 12, 12, 16, 16, 16, 16, 18, 18, 24, 24, 24, 24, 24, 24, 27, 27, 27, 32, 32, 32, 32, 32, 36, 36, 36, 36, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 54, 54, 54, 54, 54, 54, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 72, 72, 72, 72, 72, 72, 72, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Can be used, for example, to derive A084788 and A084790 from A084789. - Charles R Greathouse IV, Jul 09 2021

LINKS

Table of n, a(n) for n=1..72.

MATHEMATICA

With[{pf23=Union[Flatten[Table[Times@@@Tuples[{2, 3}, n], {n, 0, 6}]]]}, Flatten[Table[Select[pf23, #>=n&, 1], {n, 80}]]] (* Harvey P. Dale, Mar 07 2012 *)

PROG

(R) f <- function(n) nextn(n, factors = c(2, 3))

a <- matrix(1:256, ncol=1)

apply(a, 1, f)

(PARI) a(n)=my(v=List()); for(i=0, logint(n, 3)+1, my(t=3^i); t<<=if(t>n, 0, exponent(n\t)+1); listput(v, t)); Set(v)[1] \\ Charles R Greathouse IV, Jul 09 2021

CROSSREFS

Cf. A130916, A134361, A151969.

Sequence in context: A073138 A342179 A214965 * A142727 A347388 A112275

Adjacent sequences:  A134358 A134359 A134360 * A134362 A134363 A134364

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Aug 23 2009; corrected Mar 07 2012

STATUS

approved

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Last modified January 17 11:16 EST 2022. Contains 350389 sequences. (Running on oeis4.)