A048619 a(n) = LCM(binomial(n,0), ..., binomial(n,n)) / binomial(n,floor(n/2)).

1, 1, 1, 1, 2, 1, 3, 3, 4, 2, 10, 5, 30, 15, 7, 7, 56, 28, 252, 126, 60, 30, 330, 165, 396, 198, 286, 143, 2002, 1001, 15015, 15015, 7280, 3640, 1768, 884, 15912, 7956, 3876, 1938, 38760, 19380, 406980, 203490, 99484, 49742, 1144066, 572033, 1961256, 980628

Offset

0,5

Links

Table of n, a(n) for n=0..49.

Index entries for sequences related to lcm's

Formula

a(n) = A002944(n)/A001405(n).

a(n) = lcm(1..n+1)/(floor((n+3)/2)*binomial(n+1,floor((n+3)/2)). - Paul Barry, Jul 03 2006

a(n) = lcm(1,2,...,n+1) / (ceiling((n+1)/2)*binomial(n+1,floor((n+1)/2))) = A003418(n+1) / A100071(n+1). - Max Alekseyev, Oct 23 2015

a(n) = A263673(n+1) / A110654(n+1) = A180000(n+1) / A152271(n). - Max Alekseyev, Oct 23 2015

a(2*n-1) = A068553(n) = A068550(n)/n.

Example

If n=10 then A002944(10)=2520, A001405(10)=252, the quotient a(10)=10.

Mathematica

Table[Apply[LCM, Binomial[n, Range[0, n]]]/Binomial[n, Floor[n/2]], {n, 0, 48}] (* Michael De Vlieger, Jun 29 2017 *)

Prog

(PARI) {A048619(n) = lcm(vector(n+1, i, i)) / binomial(n+1, (n+1)\2) / ((n+2)\2); }
(Magma) [Lcm([1..n+1]) div (Floor((n+3)/2)*Binomial(n+1, Floor((n+3)/2))): n in [0..50]]; // Vincenzo Librandi, Jul 10 2019

Crossrefs

Cf. A001405, A002944.

Sequence in context: A144623 A340284 A218975 * A116087 A328518 A163281

Adjacent sequences: A048616 A048617 A048618 * A048620 A048621 A048622

Keyword

nonn,easy

Author

Labos Elemer

Extensions

Definition corrected and a(0)=1 prepended by Max Alekseyev, Oct 23 2015

Status

approved