A109922 a(n) = floor(lcm(1,2,...n)/(1+2+...+n)).

1, 0, 1, 1, 4, 2, 15, 23, 56, 45, 420, 355, 3960, 3432, 3003, 5299, 80080, 71650, 1225224, 1108536, 1007760, 920128, 19399380, 17847429, 82372752, 76271066, 212469400, 197816337, 5354228880, 5008794758, 145568097675, 273491577450

Offset

1,5

Links

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

Example

a(6)=2 because floor(lcm(1,2,3,4,5,6)/(1+2+3+4+5+6)) = floor(60/21) = 2.

Maple

a:=n->floor(2*lcm(seq(k, k=1..n))/n/(n+1)): seq(a(n), n=1..37); # Emeric Deutsch

Mathematica

f[n_] := Floor[ 2LCM @@ Range[n]/(n(n + 1))]; Table[ f[n], {n, 32}] (* Robert G. Wilson v, Jul 18 2005 *)

Crossrefs

Sequence in context: A121662 A130042 A285362 * A090640 A302213 A090881

Adjacent sequences: A109919 A109920 A109921 * A109923 A109924 A109925

Keyword

easy,nonn

Author

Amarnath Murthy, Jul 16 2005

Extensions

More terms from Emeric Deutsch and Robert G. Wilson v, Jul 16 2005

Status

approved