A181860 a(n) = lcm(n^2, swinging_factorial(n)).

0, 1, 4, 18, 48, 150, 180, 980, 2240, 5670, 6300, 30492, 11088, 156156, 168168, 257400, 1647360, 3719430, 3938220, 17551820, 18475600, 81477396, 85357272, 373173528, 389398464, 1690097500, 1757701400, 7582037400, 3931426800, 33738060600

Offset: 0

Author

Peter Luschny, Nov 21 2010

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000290, A056040, A170825, A181861.

Programs

Maple

A181860 := n -> ilcm(n^2,n!/iquo(n,2)!^2);

Mathematica

Join[{0},sf[n_]:=n!/Quotient[n, 2]!^2; a[n_]:=LCM[n^2, sf[n]]; Table[a[n], {n, 30}] ] (* Jean-François Alcover, Jun 28 2013 *)

PARI

a(n) = lcm(n^2, n!/(n\2)!^2); \\ Michel Marcus, Mar 06 2018

Formula

a(n) = lcm(A000290(n), A056040(n)).

Extensions

a(26)-a(29) from Vincenzo Librandi, Mar 05 2018