A191778 - OEIS

%I #10 Dec 10 2013 17:31:50

%S 1,4,24,48,480,960,13440,26880,161280,322560,7096320,14192640,

%T 369008640,738017280,1476034560,2952069120,100370350080,200740700160,

%U 7628146606080,15256293212160,30512586424320,61025172848640,2807157951037440,5614315902074880,56143159020748800

%N a(1) = 1; a(n)= 2*lcm(n, a(n - 1)).

%C n and a(n-1) divide a(n).

%t a[1] = 1; a[n_] := a[n]=2 LCM (n, a[n - 1]);Table[a[n],{n,100}]

%t RecurrenceTable[{a[1]==1,a[n]==2*LCM[n,a[n-1]]},a,{n,30}] (* _Harvey P. Dale_, Dec 10 2013 *)

%K nonn

%O 1,2

%A _José María Grau Ribas_, Jun 16 2011