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A194871 Triangular array (and fractal sequence): row n is the permutation of (1,2,...,n) obtained from the increasing ordering of fractional parts {r}, {2r}, ..., {nr}, where r=sqrt(6). 4

%I #5 Mar 30 2012 18:57:44

%S 1,1,2,3,1,2,3,1,4,2,5,3,1,4,2,5,3,1,6,4,2,7,5,3,1,6,4,2,7,5,3,1,8,6,

%T 4,2,9,7,5,3,1,8,6,4,2,9,7,5,3,1,10,8,6,4,2,9,7,5,3,1,10,8,6,4,2,11,9,

%U 7,5,3,12,1,10,8,6,4,2,11,9,7,5,3,12,1,10,8,6,4,13,2,11,9,7,5

%N Triangular array (and fractal sequence): row n is the permutation of (1,2,...,n) obtained from the increasing ordering of fractional parts {r}, {2r}, ..., {nr}, where r=sqrt(6).

%C See A194832 for a general discussion.

%e First nine rows:

%e 1

%e 1 2

%e 3 1 2

%e 3 1 4 2

%e 5 3 1 4 2

%e 5 3 1 6 4 2

%e 7 5 3 1 6 4 2

%e 7 5 3 1 8 6 4 2

%e 9 7 5 3 1 8 6 4 2

%t r = Sqrt[6];

%t t[n_] := Table[FractionalPart[k*r], {k, 1, n}];

%t f = Flatten[Table[Flatten[(Position[t[n], #1] &) /@

%t Sort[t[n], Less]], {n, 1, 20}]] (* A194871 *)

%t TableForm[Table[Flatten[(Position[t[n], #1] &) /@

%t Sort[t[n], Less]], {n, 1, 15}]]

%t row[n_] := Position[f, n];

%t u = TableForm[Table[row[n], {n, 1, 20}]]

%t g[n_, k_] := Part[row[n], k];

%t p = Flatten[Table[g[k, n - k + 1], {n, 1, 13},

%t {k, 1, n}]] (* A194872 *)

%t q[n_] := Position[p, n]; Flatten[

%t Table[q[n], {n, 1, 80}]] (* A194873 *)

%Y Cf. A194832, A194872, A194873.

%K nonn,tabl

%O 1,3

%A _Clark Kimberling_, Sep 04 2011

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Last modified April 19 15:11 EDT 2024. Contains 371794 sequences. (Running on oeis4.)