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A179661 Triangle read by rows: T(n,k) is the largest least common multiple of any k-element subset of the first n positive integers. 3

%I

%S 1,2,2,3,6,6,4,12,12,12,5,20,60,60,60,6,30,60,60,60,60,7,42,210,420,

%T 420,420,420,8,56,280,840,840,840,840,840,9,72,504,2520,2520,2520,

%U 2520,2520,2520,10,90,630,2520,2520,2520,2520,2520,2520,2520,11,110,990

%N Triangle read by rows: T(n,k) is the largest least common multiple of any k-element subset of the first n positive integers.

%C Sequence differs from A093919; first divergences are at indices 31, 40, 48, 59.

%C Main diagonal is A003418.

%F T(n,k) = max{ lcm(x_1,...,x_k) ; 0 < x_1 < ... < x_k <= n }.

%e Triangle begins:

%e [ 1 ],

%e [ 2, 2 ],

%e [ 3, 6, 6 ],

%e [ 4, 12, 12, 12 ],

%e [ 5, 20, 60, 60, 60 ],

%e [ 6, 30, 60, 60, 60, 60 ].

%t A179661[n_,k_]:=Max[LCM@@@Subsets[Range[n],{k}]];

%t A002260[n_]:=n-Binomial[Floor[1/2+Sqrt[2*n]],2];

%t A002024[n_]:=Floor[1/2+Sqrt[2*n]];

%t A179661[n_]:=A179661[A002024[n],A002260[n]]

%o (MAGMA) A179661:=func< n, k | Max([ LCM(s): s in Subsets({1..n}, k) ]) >; z:=12; [ A179661(n, k): k in [1..n], n in [1..z] ]; // _Klaus Brockhaus_, Jan 16 2011

%Y Cf. A093919, A096179, A003418.

%K nonn,tabl

%O 1,2

%A _Enrique PĂ©rez Herrero_, Jan 09 2011

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Last modified March 24 06:56 EDT 2019. Contains 321444 sequences. (Running on oeis4.)