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a(1)=a(2)=a(3)=1; for n > 3, a(n) = lcm(a(n-1) + a(n-2), a(n-3)).
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%I #15 Nov 10 2024 05:20:50

%S 1,1,1,2,3,5,8,39,235,1096,51909,2491235,348410728,6071656665789,

%T 15126791566796828495,1317584644380565684408069688,

%U 7999921680639175567165604204659004361387

%N a(1)=a(2)=a(3)=1; for n > 3, a(n) = lcm(a(n-1) + a(n-2), a(n-3)).

%H Robert Israel, <a href="/A128485/b128485.txt">Table of n, a(n) for n = 1..25</a>

%p a[1]:=1: a[2]:=1: a[3]:=1: for n from 4 to 18 do a[n]:=lcm(a[n-1]+a[n-2],a[n-3]) od: seq(a[n],n=1..18); # _Emeric Deutsch_, May 22 2007

%K nonn

%O 1,4

%A _Leroy Quet_, May 07 2007

%E More terms from _Emeric Deutsch_, May 22 2007