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 1-4 of 4 results.

A191540 Dispersion of (floor(2*n*sqrt(2))), by antidiagonals.

Original entry on oeis.org

1, 2, 3, 5, 8, 4, 14, 22, 11, 6, 39, 62, 31, 16, 7, 110, 175, 87, 45, 19, 9, 311, 494, 246, 127, 53, 25, 10, 879, 1397, 695, 359, 149, 70, 28, 12, 2486, 3951, 1965, 1015, 421, 197, 79, 33, 13, 7031, 11175, 5557, 2870, 1190, 557, 223, 93, 36, 15, 19886, 31607
Offset: 1

Views

Author

Clark Kimberling, Jun 06 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 and A191536-A191545.

Examples

			Northwest corner:
  1,  2,  5,  14,  39, ...
  3,  8, 22,  62, 175, ...
  4, 11, 31,  87, 246, ...
  6, 16, 45, 127, 359, ...
  7, 19, 53, 149, 421, ...

Links

Crossrefs

Cf. A114537, A035513, A035506.

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
r=40; r1=12; c=40; c1=12; f[n_] :=Floor[2n*Sqrt[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, r1}, {j, 1, c1}]]  (* A191540 array *)
Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191540 sequence *)

A191537 Dispersion of (4*n-floor(n*sqrt(2))), by antidiagonals.

Original entry on oeis.org

1, 3, 2, 8, 6, 4, 21, 16, 11, 5, 55, 42, 29, 13, 7, 143, 109, 75, 34, 19, 9, 370, 282, 194, 88, 50, 24, 10, 957, 730, 502, 228, 130, 63, 26, 12, 2475, 1888, 1299, 590, 337, 163, 68, 32, 14, 6400, 4882, 3359, 1526, 872, 422, 176, 83, 37, 15, 16550, 12624
Offset: 1

Views

Author

Clark Kimberling, Jun 06 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 and A191536-A191545.

Examples

			Northwest corner:
  1,  3,  8,  21,  55, ...
  2,  6, 16,  42, 109, ...
  4, 11, 29,  75, 194, ...
  5, 13, 34,  88, 228, ...
  7, 19, 50, 130, 337, ...

Links

Crossrefs

Cf. A114537, A035513, A035506.

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
r=40; r1=12; c=40; c1=12; f[n_] :=4n-Floor[n*Sqrt[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, r1}, {j, 1, c1}]]  (* A191537 array *)
Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191537 sequence *)
(* Clark Kimberling, Jun 06 2011 *)

A191538 Dispersion of (4*n-floor(n*sqrt(3))), by antidiagonals.

Original entry on oeis.org

1, 3, 2, 7, 5, 4, 16, 12, 10, 6, 37, 28, 23, 14, 8, 84, 64, 53, 32, 19, 9, 191, 146, 121, 73, 44, 21, 11, 434, 332, 275, 166, 100, 48, 25, 13, 985, 753, 624, 377, 227, 109, 57, 30, 15, 2234, 1708, 1416, 856, 515, 248, 130, 69, 35, 17, 5067, 3874, 3212, 1942
Offset: 1

Views

Author

Clark Kimberling, Jun 06 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 and A191536-A191545.

Examples

			Northwest corner:
  1,  3,  7,  16,  37, ...
  2,  5, 12,  28,  64, ...
  4, 10, 23,  53, 121, ...
  6, 14, 32,  73, 166, ...
  8, 19, 44, 100, 227, ...

Links

Crossrefs

Cf. A114537, A035513, A035506.

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
r=40; r1=12; c=40; c1=12; f[n_] :=4n-Floor[n*Sqrt[3]]   (* 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, r1}, {j, 1, c1}]]  (* A191538 array *)
Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191538 sequence *)

A191539 Dispersion of (5*n-floor(n*sqrt(5))), by antidiagonals.

Original entry on oeis.org

1, 3, 2, 9, 6, 4, 25, 17, 12, 5, 70, 47, 34, 14, 7, 194, 130, 94, 39, 20, 8, 537, 360, 260, 108, 56, 23, 10, 1485, 996, 719, 299, 155, 64, 28, 11, 4105, 2753, 1988, 827, 429, 177, 78, 31, 13, 11346, 7610, 5495, 2286, 1186, 490, 216, 86, 36, 15, 31360, 21034
Offset: 1

Views

Author

Clark Kimberling, Jun 06 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 and A191536-A191545.

Examples

			Northwest corner:
  1...3....9....25...70
  2...6....17...47...130
  4...12...34...94...260
  5...14...39...108..299
  7...20...56...155..429

Links

Crossrefs

Cf. A114537, A035513, A035506.

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
r=40; r1=12; c=40; c1=12; f[n_] :=5n-Floor[n*Sqrt[5]]   (* 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, r1}, {j, 1, c1}]]  (* A191539 array *)
Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191539 sequence *)
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.