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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A133481 Least k such that k^n divides k! but k^(n+1) does not divide k!. 5
1, 6, 15, 18, 12, 32, 24, 36, 40, 45, 48, 100, 84, 60, 154, 165, 72, 96, 80, 126, 90, 135, 286, 200, 312, 264, 168, 120, 297, 189, 160, 330, 544, 210, 144, 224, 300, 385, 396, 324, 252, 680, 350, 180, 280, 748, 572, 486, 400, 405, 315, 528, 320, 336, 450, 512, 288, 240, 715 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Least k such that A011776(k)=n.

New record highs, by index: 1, 2, 3, 4, 6, 8, 9, 10, 11, 12, 15, 16, 23, 25, 32, 33, 42, 46, 63, 66, 79, 85, 100, 119, 128, 167, 188, 201, 213, 226, 240, 256, 335, 346, 348, 352, 360, 377, 385, 414, 426, 480, 481, 494, 504, 533, 555, 596, 656, 727, 883, 926, 938, 1026, 1094, ... - Robert G. Wilson v, Feb 28 2012

REFERENCES

Ivan Niven, Herbert S. Zuckerman and Hugh L. Montgomery, An Introduction to the Theory Of Numbers, Fifth Edition, John Wiley and Sons, Inc., NY 1991.

J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 251.

LINKS

T. D. Noe and Robert G. Wilson v, Table of n, a(n) for n = 1..1150 (T. D. Noe produced 345 terms)

Index entries for sequences related to factorial numbers

EXAMPLE

a(7)=24 because 24^7|24! and smaller numbers than 24 do not divide their factorials 7 times.

MATHEMATICA

kdn[n_]:=Module[{k=2}, While[!Divisible[k!, k^n]||Divisible[k!, k^(n+1)], k++]; k]; Join[{1}, Array[kdn, 60, 2]] (* Harvey P. Dale, Feb 27 2012 *)

PROG

(PARI) a(n)=if(n<2, 1, my(k=2); while(valuation(k!, k)!=n, k++); k) \\ Charles R Greathouse IV, Feb 27 2012

CROSSREFS

Cf. A011776, A011777, A011778.

Sequence in context: A158338 A139204 A122661 * A274549 A099535 A070999

Adjacent sequences:  A133478 A133479 A133480 * A133482 A133483 A133484

KEYWORD

nice,nonn

AUTHOR

Masahiko Shin, Nov 29 2007

EXTENSIONS

Edited by N. J. A. Sloane using material from A011777, Nov 29 2007

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 18 09:13 EST 2017. Contains 294879 sequences.