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.

A259556 Rectangular array, read by antidiagonals: T(h,k) = u(h) + v(k), where u = A000201 (lower Wythoff numbers), v = A001950 (upper Wythoff numbers), and h >= 1, k >= 1.

Original entry on oeis.org

3, 6, 5, 8, 8, 6, 11, 10, 9, 8, 14, 13, 11, 11, 10, 16, 16, 14, 13, 13, 11, 19, 18, 17, 16, 15, 14, 13, 21, 21, 19, 19, 18, 16, 16, 14, 24, 23, 22, 21, 21, 19, 18, 17, 16, 27, 26, 24, 24, 23, 22, 21, 19, 19, 18, 29, 29, 27, 26, 26, 24, 24, 22, 21, 21, 19, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21
Offset: 1

Views

Author

Clark Kimberling, Jul 22 2015

Keywords

Examples

			Northwest corner:
3    6    8    11   14   16   19
5    8    10   13   16   18   21
6    9    11   14   17   19   22
8    11   13   16   19   22   24
10   13   15   18   21   23   26
11   14   16   19   22   24   27
T(2,3) = u(2) + v(3) = 3 + 7 = 10.
		

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 12;
    u[n_] := u[n] = Floor[n*r]; v[n_] := v[n] = Floor[n*r^2];
    s[m_, n_] := s[m, n] = u[m] + v[n]; t = Table[s[m, n], {m, 1, z}, {n, 1, z}]
    TableForm[t] (* A259556 array *)
    Table[s[n - k + 1, k], {n, z}, {k, n, 1, -1}] // Flatten (* A259556 sequence *)

A259600 Triangular array: sums of two distinct lower Wythoff numbers.

Original entry on oeis.org

4, 5, 7, 7, 9, 10, 9, 11, 12, 14, 10, 12, 13, 15, 17, 12, 14, 15, 17, 19, 20, 13, 15, 16, 18, 20, 21, 23, 15, 17, 18, 20, 22, 23, 25, 26, 17, 19, 20, 22, 24, 25, 27, 28, 30, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 20, 22, 23, 25, 27, 28, 30, 31, 33, 35, 36
Offset: 2

Views

Author

Clark Kimberling, Jul 22 2015

Keywords

Comments

Row n shows the numbers u(m) + u(n), where u = A000201 (lower Wythoff sequence), for m=1..n-1, for n >= 2. (The offset is 2, so that the top row is counted as row 2.)

Examples

			10 = 4 + 6 = u(3) + u(4), so that 10 appears as the final term in row 4. (The offset is 2, so that the top row is counted as row 2.) Rows 2 to 9:
4
5    7
7    9    10
9    11   12   14
10   12   13   15   17
12   14   15   17   19   20
13   15   16   18   20   21   23
15   17   18   20   22   23   25   26
		

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 20; u[n_] := u[n] = Floor[n*r];
    s[m_, n_] := u[m] + u[n]; t = Table[s[m, n], {n, 2, z}, {m, 1, n - 1}];
    TableForm[t]  (* A259600 array *)
    Flatten[t]  (* A259600 sequence *)
  • PARI
    tabl(nn) = {r=(sqrt(5)+1)/2; for (n=2, nn, for (k=1, n-1, print1(floor(n*r) + floor(k*r), ", ");); print(););} \\ Michel Marcus, Jul 30 2015

A260311 Difference sequence of A260317.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 2, 3, 2, 3, 2, 3, 3, 2, 3, 3, 2, 3, 5, 3, 2, 3, 5, 3, 2, 3, 5, 3, 5, 3, 2, 3, 5, 3, 5, 3, 2, 3, 5, 3, 5, 5, 3, 5, 3, 2, 3, 5, 3, 5, 5, 3, 5, 3, 2, 3, 5, 3, 5, 5, 3, 5, 3, 5, 5, 3, 5, 3, 2, 3, 5, 3, 5, 5, 3, 5, 3, 5, 5, 3, 5, 3
Offset: 1

Views

Author

Clark Kimberling, Jul 31 2015

Keywords

Comments

Conjecture: a(n) is a Fibonacci number (A000045) for every n.
In fact, a(n) is in {1,2,3,5}; proved with the Walnut theorem-prover. - Jeffrey Shallit, Oct 12 2022
Comment from Jonathan F. P. Grube and Benjamin Mason, Oct 10 2024 [Corrected by Jonathan F. P. Grube, Nov 05 2024]: (Start)
With an offset of 41, the sequence is of the form 2[c_{1,1},...,c_{1,n_1}]2[c_{2,1},...,c_{2,n_2}]2[c_{3,1},...,c_{3,n_3}]2..., where [c_{i,1},...,c_{i,n_i}] is the word 35(355)^{c_{i,1}}35(355)^{c_{i,2}}35...35(355)^{c_{i,n_i}}353 over the alphabet {3,5} for some nonnegative integers c_{i,j}. Furthermore c_{i,j} is in {1,2}. Proved with Walnut, the theorem-prover.
Conjectures: n_{2k-1} = n_{2k} and c_{2k-1, j} = c_{2k, j} for all positive k and 0 0} is the Fibonacci sequence. (End)

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 1060;
    u[n_] := u[n] = Floor[n*r]; v[n_] := v[n] = Floor[n*r^2];
    s[m_, n_] := v[m] + v[n];
    t = Table[s[m, n], {n, 2, z}, {m, 1, n - 1}]; (* A259601 *)
    w = Flatten[Table[Count[Flatten[t], n], {n, 1, z}]];
    p0 = Flatten[Position[w, 0]]  (* A260317 *)
    d = Differences[p0] (* A260311 *)

A260317 Numbers not of the form v(m) + v(n), where v = A001950 (upper Wythoff numbers) and 1 <= m <= n - 1, for n >= 2.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 10, 11, 13, 14, 16, 19, 21, 24, 26, 29, 32, 34, 37, 40, 42, 45, 50, 53, 55, 58, 63, 66, 68, 71, 76, 79, 84, 87, 89, 92, 97, 100, 105, 108, 110, 113, 118, 121, 126, 131, 134, 139, 142, 144, 147, 152, 155, 160, 165, 168, 173, 176, 178, 181
Offset: 1

Views

Author

Clark Kimberling, Jul 22 2015

Keywords

Comments

It appears that the difference sequence consists entirely of Fibonacci numbers (A000045); see A260311.
In fact, the difference sequence consists only of the numbers 1,2,3,5. Proved with the Walnut theorem-prover. - Jeffrey Shallit, Oct 12 2022

Crossrefs

Programs

  • Mathematica
    r = GoldenRatio; z = 1060;
    u[n_] := u[n] = Floor[n*r]; v[n_] := v[n] = Floor[n*r^2];
    s[m_, n_] := v[m] + v[n];
    t = Table[s[m, n], {n, 2, z}, {m, 1, n - 1}]; (* A259601 *)
    w = Flatten[Table[Count[Flatten[t], n], {n, 1, z}]];
    p0 = Flatten[Position[w, 0]]  (* A260317 *)
    d = Differences[p0] (* A260311 *)

Formula

n <= a(n) < 5n, see Shallit comment. - Charles R Greathouse IV, Nov 22 2024
Showing 1-4 of 4 results.