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A174557 Triangle T(n, k) = -floor(n/k) with T(n, n) = 1, read by rows.

%I A174557 #10 Mar 07 2021 03:05:27
%S A174557 1,-2,1,-3,-1,1,-4,-2,-1,1,-5,-2,-1,-1,1,-6,-3,-2,-1,-1,1,-7,-3,-2,-1,
%T A174557 -1,-1,1,-8,-4,-2,-2,-1,-1,-1,1,-9,-4,-3,-2,-1,-1,-1,-1,1,-10,-5,-3,
%U A174557 -2,-2,-1,-1,-1,-1,1,-11,-5,-3,-2,-2,-1,-1,-1,-1,-1,1,-12,-6,-4,-3,-2,-2,-1,-1,-1,-1,-1,1
%N A174557 Triangle T(n, k) = -floor(n/k) with T(n, n) = 1, read by rows.
%H A174557 G. C. Greubel, <a href="/A174557/b174557.txt">Rows n = 1..30 of the triangle, flattened</a>
%F A174557 T(n, k) = A010766(n, k)*A154990(n, k).
%F A174557 T(n, k) = -floor(n/k) with T(n, n) = 1. - _G. C. Greubel_, Mar 06 2021
%e A174557 Table begins:
%e A174557     1;
%e A174557    -2,  1;
%e A174557    -3, -1,  1;
%e A174557    -4, -2, -1,  1;
%e A174557    -5, -2, -1, -1,  1;
%e A174557    -6, -3, -2, -1, -1,  1;
%e A174557    -7, -3, -2, -1, -1, -1,  1;
%e A174557    -8, -4, -2, -2, -1, -1, -1,  1;
%e A174557    -9, -4, -3, -2, -1, -1, -1, -1,  1;
%e A174557   -10, -5, -3, -2, -2, -1, -1, -1, -1, 1;
%t A174557 Table[If[k==n, 1, -Floor[n/k]], {n,12}, {k,n}]//Flatten (* _G. C. Greubel_, Mar 06 2021 *)
%o A174557 (Sage) flatten([[1 if k==n else -(n//k) for k in [1..n]] for n in [1..12]]) # _G. C. Greubel_, Mar 06 2021
%o A174557 (Magma) [k eq n select 1 else -Floor(n/k): k in [1..n], n in [1..12]]; // _G. C. Greubel_, Mar 06 2021
%Y A174557 Cf. A010766, A154990.
%K A174557 sign,tabl
%O A174557 1,2
%A A174557 _Mats Granvik_, _Paul D. Hanna_, Mar 22 2010