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Rectangular array, by antidiagonals: row n gives the positions of n in the fractal sequence A194877; an interspersion.
4

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

%S 1,3,2,6,5,4,10,9,8,7,15,14,13,12,11,20,19,18,17,16,21,27,25,24,23,22,

%T 28,26,35,33,31,30,29,36,34,32,44,42,40,38,37,45,43,41,39,54,52,50,48,

%U 46,55,53,51,49,47,65,63,61,59,57,66,64,62,60,58,56,76,74,72

%N Rectangular array, by antidiagonals: row n gives the positions of n in the fractal sequence A194877; an interspersion.

%C See A194832 for a general discussion.

%e Northwest corner:

%e 1...3...6...10..15..20..27

%e 2...5...9...14..19..25..33

%e 4...8...13..18..24..31..40

%e 7...12..17..23..30..38..48

%e 11..16..22..29..37..46..57

%t r = Sqrt[8];

%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}]] (* A194877 *)

%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}]] (* A194878 *)

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

%t {n, 1, 80}]] (* A194879 *)

%Y Cf. A194832, A194877, A194879.

%K nonn,tabl

%O 1,2

%A _Clark Kimberling_, Sep 04 2011