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%I #13 Sep 26 2020 11:42:55
%S 1,2,3,2,3,5,2,3,5,7,4,5,6,7,9,4,5,6,7,9,11,4,5,6,7,9,11,13,4,6,7,9,
%T 10,11,13,15,4,6,7,9,10,11,13,15,17,4,6,7,9,10,11,13,15,17,19,4,6,9,
%U 10,11,13,14,15,17,19,21,4,6,9,10,11,13,14,15,17,19,21,23,4,6,9,10,11,13,14
%N Triangular array (read by rows) containing the least n integers < 2n such that no integer divides another.
%C The first number on each row is 2^k, where k is the greatest integer such that (3^k)/2 < n.
%e 1;
%e 2, 3;
%e 2, 3, 5;
%e 2, 3, 5, 7;
%e 4, 5, 6, 7, 9;
%e 4, 5, 6, 7, 9, 11;
%e 4, 5, 6, 7, 9, 11, 13;
%e 4, 6, 7, 9, 10, 11, 13, 15;
%t noneDivQ[L_] := NoneTrue[Subsets[L, {2}], Divisible[#[[2]], #[[1]]]&];
%t k1[n_] := For[k = Log[3, 2n]//Ceiling, True, k--, If[(3^k)/2<n, Return[k]]];
%t row[n_] := SelectFirst[Subsets[Range[2^k1[n], 2n-1], {n}], noneDivQ];
%t Array[row, 13] // Flatten (* _Jean-François Alcover_, Sep 25 2020 *)
%Y Cf. A174062, A174094.
%K nonn,tabl
%O 1,2
%A _David Brown_, Mar 07 2010
%E Definition corrected by _David Brown_, Mar 20 2010
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