Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the 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