A124444 a(n) = LCM of the integers, from n/2 to n, which are coprime to n.

1, 1, 2, 3, 12, 5, 60, 35, 280, 63, 2520, 77, 27720, 1287, 8008, 6435, 720720, 2431, 12252240, 46189, 3695120, 440895, 232792560, 96577, 1070845776, 3900225, 2974571600, 5014575, 80313433200, 215441, 2329089562800, 31556720475

Offset

1,3

Links

Table of n, a(n) for n=1..32.

Example

The integers which are >= 9/2 and are <= 9 and which are coprime to 9 are 5, 7 and 8. So a(9) = lcm(5,7,8) = 280.

Mathematica

f[n_] := LCM @@ Select[Range[Ceiling[n/2], n], GCD[ #, n] == 1 &]; Table[f[n], {n, 33}] (* Ray Chandler, Nov 12 2006 *)

Prog

(PARI) a(n) = lcm(select(x->(gcd(x, n)==1), vector(n\2, k, n\2+k))); \\ Michel Marcus, Mar 18 2018

Crossrefs

Cf. A124443.

Sequence in context: A281850 A282216 A245678 * A038610 A334313 A325760

Adjacent sequences: A124441 A124442 A124443 * A124445 A124446 A124447

Keyword

nonn

Author

Leroy Quet, Nov 01 2006

Extensions

Extended by Ray Chandler, Nov 12 2006

Status

approved