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A008339 a(1)=1; for n >= 1, a(n+1) = lcm(a(n),n) / gcd(a(n),n). 4
1, 1, 2, 6, 6, 30, 5, 35, 280, 2520, 252, 2772, 231, 3003, 858, 1430, 5720, 97240, 437580, 8314020, 415701, 969969, 176358, 4056234, 2704156, 67603900, 2600150, 70204050, 10029150, 290845350, 9694845, 300540195, 9617286240, 35263382880, 1037158320 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n+1) = Product(A098666(n,k): 1<=k<=n), row-products of triangle A098666. - Reinhard Zumkeller, Sep 20 2004

a(n+1) is divisible by all primes in (n/2, n]; thus lim_{n->infinity} a(n) = infinity. - Franklin T. Adams-Watters, Dec 13 2006

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(1) = 1, a(n) = a(n-1)*r/s where y is the largest divisor of a(n-1) with r*s = n. - Amarnath Murthy, Jul 01 2003

a(1) = 1, a(n+1) = a(n)*n/gcd(a(n),n)^2. - Franklin T. Adams-Watters, Dec 13 2006

MAPLE

A008339 := proc(n) option remember; if n = 1 then 1 else lcm(A008339(n-1), n-1)/gcd(A008339(n-1), n-1); fi; end;

MATHEMATICA

FoldList[ LCM[ #1, #2 ]/GCD[ #1, #2 ]&, 1, Range[ 30 ] ] (* Olivier Gérard, Aug 15 1997 *)

CROSSREFS

Cf. A249831.

Sequence in context: A055204 A212397 * A077139 A068629 A144361 A163641

Adjacent sequences:  A008336 A008337 A008338 * A008340 A008341 A008342

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 13 19:25 EST 2018. Contains 317149 sequences. (Running on oeis4.)