This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A181860 #22 Mar 12 2018 03:50:31
%S A181860 0,1,4,18,48,150,180,980,2240,5670,6300,30492,11088,156156,168168,
%T A181860 257400,1647360,3719430,3938220,17551820,18475600,81477396,85357272,
%U A181860 373173528,389398464,1690097500,1757701400,7582037400,3931426800,33738060600
%N A181860 a(n) = lcm(n^2, swinging_factorial(n)).
%H A181860 Vincenzo Librandi, <a href="/A181860/b181860.txt">Table of n, a(n) for n = 0..1000</a>
%F A181860 a(n) = lcm(A000290(n), A056040(n)).
%p A181860 A181860 := n -> ilcm(n^2,n!/iquo(n,2)!^2);
%t A181860 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 *)
%o A181860 (PARI) a(n) = lcm(n^2, n!/(n\2)!^2); \\ _Michel Marcus_, Mar 06 2018
%Y A181860 Cf. A000290, A056040, A170825, A181861.
%K A181860 nonn
%O A181860 0,3
%A A181860 _Peter Luschny_, Nov 21 2010
%E A181860 a(26)-a(29) from _Vincenzo Librandi_, Mar 05 2018