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A191545 Dispersion of (floor(9n/4)), by antidiagonals. 6

%I #7 Feb 13 2014 13:24:38

%S 1,2,3,4,6,5,9,13,11,7,20,29,24,15,8,45,65,54,33,18,10,101,146,121,74,

%T 40,22,12,227,328,272,166,90,49,27,14,510,738,612,373,202,110,60,31,

%U 16,1147,1660,1377,839,454,247,135,69,36,17,2580,3735,3098,1887

%N Dispersion of (floor(9n/4)), by antidiagonals.

%C Background discussion: Suppose that s is an increasing sequence of positive integers, that the complement t of s is infinite, and that t(1)=1. The dispersion of s is the array D whose n-th row is (t(n), s(t(n)), s(s(t(n)), s(s(s(t(n)))), ...). Every positive integer occurs exactly once in D, so that, as a sequence, D is a permutation of the positive integers. The sequence u given by u(n)=(number of the row of D that contains n) is a fractal sequence. Examples:

%C (1) s=A000040 (the primes), D=A114537, u=A114538.

%C (2) s=A022343 (without initial 0), D=A035513 (Wythoff array), u=A003603.

%C (3) s=A007067, D=A035506 (Stolarsky array), u=A133299.

%C More recent examples of dispersions: A191426-A191455.

%e Northwest corner:

%e 1...2....4....9....20

%e 3...6....13...29...65

%e 5...11...25...54...121

%e 7...15...33...74...166

%e 8...18...40...90...202

%t (* Program generates the dispersion array T of the complement of increasing sequence f[n] *)

%t r=40; r1=12; c=40; c1=12; f[n_] :=Floor[9n/4]] (* complement of column 1 *)

%t mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]

%t rows = {NestList[f, 1, c]};

%t Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];

%t t[i_, j_] := rows[[i, j]];

%t TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]]

%t (* A191545 array *)

%t Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191545 sequence *)

%t (* Program by _Peter J. C. Moses_, Jun 01 2011 *)

%Y Cf. A114537, A035513, A035506.

%K nonn,tabl

%O 1,2

%A _Clark Kimberling_, Jun 09 2011

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Last modified March 28 07:20 EDT 2024. Contains 371235 sequences. (Running on oeis4.)