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A112769 Numbers with more than one prime factor and, in the ordered factorization, at least one exponent is less than the previous exponent when read from left to right. 12
12, 20, 24, 28, 40, 44, 45, 48, 52, 56, 60, 63, 68, 72, 76, 80, 84, 88, 90, 92, 96, 99, 104, 112, 116, 117, 120, 124, 126, 132, 135, 136, 140, 144, 148, 152, 153, 156, 160, 164, 168, 171, 172, 175, 176, 180, 184, 188, 189, 192, 198, 200, 204, 207, 208, 212, 220 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
It appears that this sequence lists the integers x such that A085079(n) > n. - Michel Marcus, Jul 30 2015
LINKS
EXAMPLE
90 = 2^1 * 3^2 * 5^1 and 2 > 1, so 90 is in sequence.
MATHEMATICA
mopfQ[n_]:=Module[{e=FactorInteger[n][[All, 2]]}, Length[e]>1&&Min[ Differences[ e]]<0]; Select[Range[300], mopfQ] (* Harvey P. Dale, May 30 2018 *)
PROG
(PARI) isok(n) = {f = factor(n)[, 2]; if (#f > 1, for (k=2, #f, if (f[k] < f[k-1], return (1)); ); ); return (0); } \\ Michel Marcus, Jul 30 2015
CROSSREFS
Sequence in context: A316597 A329142 A362620 * A360253 A097320 A332956
KEYWORD
nonn
AUTHOR
Ray Chandler, Sep 23 2005, based on a suggestion from Leroy Quet
STATUS
approved

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Last modified July 13 02:27 EDT 2024. Contains 374260 sequences. (Running on oeis4.)