Svoboda | Graniru | BBC Russia | Golosameriki | Facebook
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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).
Numbers that set a record for the number of divisors of least prime signature (A322584). - Hal M. Switkay, Aug 20 2024
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
Subsequence of A025487.
Cf. A085082, A182860, A182862 (unitary version), A322584.
Sequence in context: A358513 A004653 A115386 * A058771 A358512 A036493
KEYWORD
nonn,changed
AUTHOR
Amiram Eldar, Feb 19 2019
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 29 19:56 EDT 2024. Contains 375518 sequences. (Running on oeis4.)