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A117214 a(n) = (A117213(n))/(n-th squarefree positive integer). 4
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
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.
Sequence in context: A027642 A249306 A347427 * A185972 A182918 A134301
KEYWORD
nonn
AUTHOR
Leroy Quet, Mar 03 2006
EXTENSIONS
More terms from Franklin T. Adams-Watters, Oct 09 2006
STATUS
approved

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Last modified May 20 05:07 EDT 2024. Contains 372703 sequences. (Running on oeis4.)