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.

A195071 Inverse permutation of A194922; every positive integer occurs exactly once.

Original entry on oeis.org

1, 3, 2, 6, 5, 4, 9, 10, 8, 7, 13, 15, 14, 12, 11, 18, 21, 20, 19, 17, 16, 24, 27, 28, 26, 25, 23, 22, 31, 34, 36, 35, 33, 32, 30, 29, 39, 42, 45, 44, 43, 41, 40, 38, 37, 48, 51, 55, 54, 53, 52, 50, 49, 47, 46, 58, 61, 65, 66, 64, 63, 62, 60, 59, 57, 56, 69, 72, 76
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Crossrefs

Programs

  • Mathematica
    r = Sqrt[2]; p[n_] := n - Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194920 *)
    g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]]
    f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]]
    f[20]  (* A194921 *)
    row[n_] := Position[f[30], n];
    u = TableForm[Table[row[n], {n, 1, 5}]]
    v[n_, k_] := Part[row[n], k];
    w = Flatten[Table[v[k, n - k + 1], {n, 1, 13},
    {k, 1, n}]]  (* A194922 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]   (* A195071 *)

A194920 a(n) = n - floor(n/sqrt(2)).

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Comments

a(n) is the number of zeros in row n+1 in triangle A255195. - Mats Granvik, Feb 18 2015.

Crossrefs

Cf. A194921.

Programs

  • Magma
    [n-Floor(n/Sqrt(2)): n in [1..80] ]; // Vincenzo Librandi, Sep 10 2011
    
  • Mathematica
    r = Sqrt[2]; p[n_] := n - Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194920 *)
    g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]]
    f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]]
    f[20]  (* A194921 *)
    row[n_] := Position[f[30], n];
    u = TableForm[Table[row[n], {n, 1, 5}]]
    v[n_, k_] := Part[row[n], k];
    w = Flatten[Table[v[k, n - k + 1], {n, 1, 13},
    {k, 1, n}]]  (* A194922 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]   (* A195071 *)
  • PARI
    vector(100,n,n-floor(n/sqrt(2))) \\ Derek Orr, Feb 28 2015

A194921 Fractalization of (n - [n/sqrt(2)]), where [ ]=floor.

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 3, 4, 2, 1, 3, 5, 4, 2, 1, 3, 6, 5, 4, 2, 1, 3, 6, 7, 5, 4, 2, 1, 3, 6, 8, 7, 5, 4, 2, 1, 3, 6, 9, 8, 7, 5, 4, 2, 1, 3, 6, 10, 9, 8, 7, 5, 4, 2, 1, 3, 6, 10, 11, 9, 8, 7, 5, 4, 2, 1, 3, 6, 10, 12, 11, 9, 8, 7, 5, 4, 2, 1, 3, 6, 10, 13, 12, 11, 9, 8, 7, 5, 4, 2, 1, 3, 6, 10
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. The sequence (n-[n/sqrt(2)]) is A194920.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[2]; p[n_] := n - Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194920 *)
    g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]]
    f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]]
    f[20]  (* A194921 *)
    row[n_] := Position[f[30], n];
    u = TableForm[Table[row[n], {n, 1, 5}]]
    v[n_, k_] := Part[row[n], k];
    w = Flatten[Table[v[k, n - k + 1], {n, 1, 13},
    {k, 1, n}]]  (* A194922 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]   (* A195071 *)
Showing 1-3 of 3 results.