cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A191443 Dispersion of the sequence ([n*sqrt(3)+1]), where [ ]=floor, read by antidiagonals.

Original entry on oeis.org

1, 2, 3, 4, 6, 5, 7, 11, 9, 8, 13, 20, 16, 14, 10, 23, 35, 28, 25, 18, 12, 40, 61, 49, 44, 32, 21, 15, 70, 106, 85, 77, 56, 37, 26, 17, 122, 184, 148, 134, 97, 65, 46, 30, 19, 212, 319, 257, 233, 169, 113, 80, 52, 33, 22, 368, 553, 446, 404, 293, 196, 139
Offset: 1

Views

Author

Clark Kimberling, Jun 04 2011

Keywords

Comments

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:
(1) s=A000040 (the primes), D=A114537, u=A114538.
(2) s=A022343 (without initial 0), D=A035513 (Wythoff array), u=A003603.
(3) s=A007067, D=A035506 (Stolarsky array), u=A133299.
More recent examples of dispersions: A191426-A191455.

Examples

			Northwest corner:
  1....2....4....7....13
  3....6....11...20...35
  5....9....16...28...49
  8....14...25...44...77
  10...18...32...56...97
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of increasing sequence f[n] *)
    r=40; r1=12; c=40; c1=12;  x = Sqrt[3];
    f[n_] := Floor[n*x+1] (* complement of column 1 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]]
    (* A191443 array *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191443 sequence *)
    (* Program by Peter J. C. Moses, Jun 01 2011 *)

A191444 Dispersion of ([n*sqrt(3)+3/2]), where [ ]=floor, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 4, 5, 11, 8, 10, 7, 20, 15, 18, 13, 9, 36, 27, 32, 24, 17, 12, 63, 48, 56, 43, 30, 22, 14, 110, 84, 98, 75, 53, 39, 25, 16, 192, 146, 171, 131, 93, 69, 44, 29, 19, 334, 254, 297, 228, 162, 121, 77, 51, 34, 21, 580, 441, 515, 396, 282, 211, 134
Offset: 1

Views

Author

Clark Kimberling, Jun 04 2011

Keywords

Comments

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:
(1) s=A000040 (the primes), D=A114537, u=A114538.
(2) s=A022343 (without initial 0), D=A035513 (Wythoff array), u=A003603.
(3) s=A007067, D=A035506 (Stolarsky array), u=A133299.
More recent examples of dispersions: A191426-A191455.

Examples

			Northwest corner:
  1....3....6....11...20
  2....4....8....15...27
  5....10...18...32...56
  7....13...24...43...75
  9....17...30...53...93
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of increasing sequence f[n] *)
    r=40; r1=12; c=40; c1=12;  x = Sqr[3];
    f[n_] := Floor[n*x+3/2] (* complement of column 1 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]]
    (* A191444 array *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191444 sequence *)
    (* Program by Peter J. C. Moses, Jun 01 2011 *)

A191445 Dispersion of ([(n+1)*sqrt(3)]), where [ ]=floor, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 5, 4, 12, 10, 8, 7, 22, 19, 15, 13, 9, 39, 34, 27, 24, 17, 11, 69, 60, 48, 43, 31, 20, 14, 121, 105, 84, 76, 55, 36, 25, 16, 211, 183, 147, 133, 96, 64, 45, 29, 18, 367, 318, 256, 232, 168, 112, 79, 51, 32, 21, 637, 552, 445, 403, 292, 195, 138
Offset: 1

Views

Author

Clark Kimberling, Jun 04 2011

Keywords

Comments

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:
(1) s=A000040 (the primes), D=A114537, u=A114538.
(2) s=A022343 (without initial 0), D=A035513 (Wythoff array), u=A003603.
(3) s=A007067, D=A035506 (Stolarsky array), u=A133299.
More recent examples of dispersions: A191426-A191455.

Examples

			Northwest corner:
  1...3...6...12..22
  2...5...10..19..34
  4...8...15..27..48
  7...13..24..43..76
  9...17..31..55..96
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of increasing sequence f[n] *)
    r=40; r1=12; c=40; c1=12;  x = Sqr[3];
    f[n_] := Floor[n*x+x] (* complement of column 1 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]]
    (* A191445 array *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191445 sequence *)
    (* Program by Peter J. C. Moses, Jun 01 2011 *)
Showing 1-3 of 3 results.