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a(n) = lcm(1,...,2n+2)/2.
3

%I #22 Sep 08 2022 08:45:25

%S 1,6,30,420,1260,13860,180180,360360,6126120,116396280,116396280,

%T 2677114440,13385572200,40156716600,1164544781400,72201776446800,

%U 72201776446800,72201776446800,2671465728531600,2671465728531600

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

%H Vaclav Kotesovec, <a href="/A119634/b119634.txt">Table of n, a(n) for n = 0..1000</a>

%H Vaclav Kotesovec, <a href="/A119634/a119634.jpg">Plot of log(a(n))/n for n = 1..10000</a>

%t Table[LCM @@ Range[2*n + 2]/2, {n, 0, 20}] (* _Vaclav Kotesovec_, Mar 04 2019 *)

%o (GAP) List([0..20],n->Lcm(List([1..2*n+2]))/2); # _Muniru A Asiru_, Mar 04 2019

%o (PARI) {a(n) = lcm(vector(2*n+2, i, i))/2}; \\ _G. C. Greubel_, Mar 05 2019

%o (Magma) [LCM([1..2*n+2])/2: n in [0..20]]; // _G. C. Greubel_, Mar 05 2019

%o (Sage) [lcm(range(1,2*n+3))/2 for n in (0..20)] # _G. C. Greubel_, Mar 05 2019

%Y Cf. A003418.

%Y Column k=0 of A120101.

%K nonn

%O 0,2

%A _Paul Barry_, Jun 09 2006