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.

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 *)

A194922 Interspersion fractally induced by A194920, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 5, 4, 10, 9, 7, 8, 15, 14, 11, 13, 12, 21, 20, 16, 19, 18, 17, 28, 27, 22, 26, 25, 23, 24, 36, 35, 29, 34, 33, 30, 32, 31, 45, 44, 37, 43, 42, 38, 41, 40, 39, 55, 54, 46, 53, 52, 47, 51, 50, 49, 48, 66, 65, 56, 64, 63, 57, 62, 61, 60, 58, 59, 78, 77, 67
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. Every pair of rows eventually intersperse. As a sequence, A194922 is a permutation of the positive integers, with inverse A195071.

Examples

			Northwest corner:
   1,  3,  6, 10, 15, 21
   2,  5,  9, 14, 20, 27, 35
   4,  7, 11, 16, 22, 29, 37
   8, 13, 19, 26, 34, 43, 53
  12, 18, 25, 33, 42, 52, 63
		

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.