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 A068553 a(n) = lcm(1,2,...,2n) / (n*binomial(2n, n)). 6
 1, 1, 1, 3, 2, 5, 15, 7, 28, 126, 30, 165, 198, 143, 1001, 15015, 3640, 884, 7956, 1938, 19380, 203490, 49742, 572033, 980628, 240350, 3124550, 766935, 188370, 2731365, 40970475, 20160075, 4962480, 81880920, 20173560, 353037300 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Known to be always an integer. LINKS Robert Israel, Table of n, a(n) for n = 1..3774 Hojoo Lee, Re: LCM [1,2,..,N] > 2^{N-1}, NMBRTHRY Mailing List, Feb 18 2002. FORMULA a(n) = A068550(n)/n. a(n) = A048619(2*n-1). MAPLE Num:= 2: Den:=2: Res:= 1: for n from 2 to 100 do   Num:= ilcm(Num, 2*n-1, 2*n);   Den:= Den*(4+2/(n-1));   Res:= Res, Num/Den; od: Res; # Robert Israel, Dec 26 2018 MATHEMATICA Table[(LCM@@Range[2n])/(n Binomial[2n, n]), {n, 40}] (* Harvey P. Dale, Jul 17 2012 *) CROSSREFS Bisection of A048619. Sequence in context: A092935 A137455 A111273 * A174909 A187943 A301493 Adjacent sequences:  A068550 A068551 A068552 * A068554 A068555 A068556 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Mar 23 2002 STATUS approved

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Last modified December 9 22:27 EST 2019. Contains 329880 sequences. (Running on oeis4.)