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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117214 a(n) = (A117213(n))/(n-th squarefree positive integer). 3
1, 1, 2, 6, 1, 30, 3, 210, 2310, 15, 2, 30030, 510510, 10, 105, 9699690, 1155, 223092870, 1, 6469693230, 70, 15015, 6, 200560490130, 255255, 770, 7420738134810, 5, 304250263527210, 4849845, 13082761331670030, 10010 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Product of all primes up to greatest prime factor of n-th squarefree number that do not divide the n-th squarefree number. - Franklin T. Adams-Watters, Oct 09 2006

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

EXAMPLE

10 is the 7th squarefree integer. And 2*3*5 = 30 is the smallest primorial number divisible by 10 = 2*5. So a(7) = 30/10 = 3.

MATHEMATICA

Product[Prime@ i, {i, PrimePi@ FactorInteger[#][[-1, 1]]}]/# & /@ Select[Range@ 52, SquareFreeQ] (* Michael De Vlieger, Sep 30 2017 *)

PROG

(Haskell)

a117214 n = product $

   filter ((> 0) . (mod m)) $ takeWhile (< a006530 m) a000040_list

   where m = a005117 n

-- Reinhard Zumkeller, Jan 14 2012

CROSSREFS

Cf. A117213.

Cf. A006530, A005117, A073482, A073483.

Sequence in context: A291646 A027642 A249306 * A185972 A182918 A134301

Adjacent sequences:  A117211 A117212 A117213 * A117215 A117216 A117217

KEYWORD

nonn

AUTHOR

Leroy Quet, Mar 03 2006

EXTENSIONS

More terms from Franklin T. Adams-Watters, Oct 09 2006

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 February 18 03:43 EST 2018. Contains 299298 sequences. (Running on oeis4.)