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A091453 Triangular array T(n,k) read by rows in which row n consists of the numbers floor(2n/k), k=1,2,...,2n+1.

%I A091453 #15 Oct 02 2019 11:26:39
%S A091453 0,0,2,1,0,4,2,1,1,0,6,3,2,1,1,1,0,8,4,2,2,1,1,1,1,0,10,5,3,2,2,1,1,1,
%T A091453 1,1,0,12,6,4,3,2,2,1,1,1,1,1,1,0,14,7,4,3,2,2,2,1,1,1,1,1,1,1,0,16,8,
%U A091453 5,4,3,2,2,2,1,1,1,1,1,1,1,1,0,18,9,6,4,3,3,2,2,2,1,1,1,1,1,1,1,1,1,0,20,10,6
%N A091453 Triangular array T(n,k) read by rows in which row n consists of the numbers floor(2n/k), k=1,2,...,2n+1.
%H A091453 Andrew Howroyd, <a href="/A091453/b091453.txt">Table of n, a(n) for n = 0..10201</a>
%F A091453 a(n) = floor(1/(sqrt(n)-floor(sqrt(n)))) for n not a square; a(n) = 0 otherwise. - _Andrew Howroyd_, Oct 02 2019
%e A091453 First five rows:
%e A091453   0
%e A091453   0 2 1
%e A091453   0 4 2 1 1
%e A091453   0 6 3 2 1 1 1
%e A091453   0 8 4 2 2 1 1 1 1
%o A091453 (PARI) T(n, k) = 2*n\k;
%o A091453 tabf(nn) = for (n=0, nn, for (k=1, 2*n+1, print1(T(n,k), ", ")); print()); \\ _Michel Marcus_, Sep 30 2016
%o A091453 (PARI) a(n)={if(n<1, 0, my(t=sqrtint(n-1)); 2*t\(n-t^2))} \\ _Andrew Howroyd_, Oct 02 2019
%Y A091453 Cf. A013942 (without first column).
%Y A091453 Cf. A091449, A327898.
%K A091453 nonn,tabf
%O A091453 0,3
%A A091453 _Clark Kimberling_, Feb 03 2004
%E A091453 Offset corrected and missing a(99) inserted by _Andrew Howroyd_, Oct 02 2019