login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A260633 Numbers that set new records for the most ordered prime factorizations. 3
1, 6, 12, 24, 30, 60, 120, 180, 360, 720, 840, 1080, 1260, 1680, 2160, 2520, 4320, 5040, 7560, 10080, 12600, 15120, 25200, 30240, 45360, 50400, 60480, 75600, 90720, 110880, 120960, 151200, 226800, 277200, 302400, 453600, 604800, 665280, 831600, 907200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If a prime is a divisor of a(n) it is also a divisor of a(n+1).

A260987(n) = A008480(a(n)). - Reinhard Zumkeller, Nov 18 2015

Hernane and Nicolas named these numbers h-champion numbers (the function h(n) is A008480). - Amiram Eldar, Aug 20 2019

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..2011 (terms 1..80 from Reinhard Zumkeller)

Marc Deléglise, Tables des 785 premiers champions de la fonction h(n), alternative link (pdf format).

Mohand-Ouamar Hernane and Jean-Louis Nicolas, Grandes valeurs du nombre de factorisations d’un entier en produit ordonné de facteurs premiers, The Ramanujan Journal, Vol. 14, No. 2 (2007), pp. 277-304, alternative link.

EXAMPLE

See A260987.

MATHEMATICA

t = {1}~Join~Array[Multinomial @@ Last@ Transpose@ FactorInteger@ # &, 5*10^6, 2]; m = {1}; a = {1}; Do[If[t[[k]] > Max@ m, AppendTo[m, t[[k]]]; AppendTo[a, k]], {k, 2, Length@ t}]; a (* Michael De Vlieger, Nov 12 2015, after Olivier Gérard at A008480 *)

PROG

(Haskell)

a260633 n = a260633_list !! (n-1)

-- where a260633_list is defined in A260987.

-- Reinhard Zumkeller, Nov 18 2015

CROSSREFS

Record high values of A008480.

Cf. A260987.

Sequence in context: A071611 A216453 A119500 * A110967 A000082 A263849

Adjacent sequences:  A260630 A260631 A260632 * A260634 A260635 A260636

KEYWORD

nonn

AUTHOR

Gordon Hamilton, Nov 11 2015

EXTENSIONS

More terms from Michael De Vlieger, Nov 12 2015

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 03:21 EDT 2019. Contains 328335 sequences. (Running on oeis4.)