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A306491 Numbers that set a record for the number of distinct prime signatures represented among their divisors (A085082). 1
1, 2, 4, 8, 12, 24, 48, 96, 144, 192, 288, 480, 576, 720, 1152, 1440, 2880, 4320, 5760, 8640, 11520, 17280, 34560, 51840, 69120, 103680, 120960, 138240, 207360, 241920, 345600, 362880, 414720, 483840, 604800, 725760, 829440, 967680, 1209600, 1451520, 1814400 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The records are 1, 2, 3, 4, 5, 7, 9, 11, 12, 13, 15, 16, 18, 19, 21, 24, 29, 30, 34, 37, 39, 44, 51, 52, 58, 61, 62, 65, 70, ... (see the link for more values).
LINKS
MATHEMATICA
ps[1] = {}; ps[n_] := FactorInteger[n][[All, 2]] // Sort; a[n_] := ps /@ Divisors[n] // Union // Length; s={}; am=0; Do[a1=a[n]; If[a1>am, am=a1; AppendTo[s, n]], {n, 1, 2*10^6}]; s (* after Jean-François Alcover at A085082 *)
CROSSREFS
Cf. A085082, A182860, A182862 (unitary version).
Sequence in context: A358513 A004653 A115386 * A058771 A358512 A036493
KEYWORD
nonn
AUTHOR
Amiram Eldar, Feb 19 2019
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)