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a(1)=1. a(n+1) = n!/lcm(a(1),a(2),...,a(n)).
2

%I #13 Aug 24 2015 02:28:51

%S 1,1,2,3,4,10,12,84,96,108,120,1320,1440,18720,20160,151200,483840,

%T 1028160,1088640,2298240,2419200,50803200,159667200,1836172800,

%U 1916006400,11975040000,12454041600,336259123200,348713164800

%N a(1)=1. a(n+1) = n!/lcm(a(1),a(2),...,a(n)).

%H Harvey P. Dale, <a href="/A131120/b131120.txt">Table of n, a(n) for n = 1..897</a>

%e The LCM of the first 7 terms is 60. So a(8) = 7!/60 = 84.

%p A131120 := proc(n) option remember ; if n = 1 then 1; else (n-1)!/lcm(seq(A131120(i),i=1..n-1)) ; fi ; end: seq(A131120(n),n=1..40) ; # _R. J. Mathar_, Oct 17 2007

%t nxt[{a_,n_,lst_}]:=Module[{l2=lst,x=(n+1)!/LCM@@lst},{x,n+1,AppendTo[ l2,x]}]; Transpose[NestList[nxt,{1,0,{1}},30]][[1]] (* _Harvey P. Dale_, Jun 07 2014 *)

%Y Cf. A131121.

%K nonn

%O 1,3

%A _Leroy Quet_, Jun 15 2007

%E More terms from _R. J. Mathar_, Oct 17 2007