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.

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A205441 Least h such that n divides the h-th difference between distinct odd-indexed Fibonacci numbers; the differences are ordered as in A205371.

Original entry on oeis.org

1, 2, 3, 2, 15, 4, 10, 6, 21, 19, 5, 4, 28, 13, 55, 8, 45, 21, 14, 19, 10, 11, 78, 21, 325, 34, 171, 13, 9, 64, 35, 8, 7, 45, 210, 21, 190, 14, 105, 120, 55, 13, 253, 11, 465, 78, 36, 21, 406, 349, 171, 34, 378, 171, 15, 78, 18, 16, 119, 64
Offset: 1

Views

Author

Clark Kimberling, Jan 27 2012

Keywords

Comments

For a guide to related sequences, see A204892.

Crossrefs

Programs

  • Mathematica
    (See the program at A205442.)

A205442 Least k such that n divides s(k)-s(j) for some j

Original entry on oeis.org

2, 3, 3, 3, 6, 4, 5, 4, 7, 7, 4, 4, 8, 6, 11, 5, 10, 7, 6, 7, 5, 6, 13, 7, 26, 9, 19, 6, 5, 12, 9, 5, 5, 10, 21, 7, 20, 6, 15, 16, 11, 6, 23, 6, 31, 13, 9, 7, 29, 27, 19, 9, 28, 19, 6, 13, 7, 7, 16, 12
Offset: 1

Views

Author

Clark Kimberling, Jan 27 2012

Keywords

Comments

See A204892 for a discussion and guide to related sequences.

Crossrefs

Programs

  • Mathematica
    s[n_] := s[n] = Fibonacci[2*n - 1]; z1 = 500; z2 = 60;
    Table[s[n], {n, 1, 30}]         (* A001519 *)
    u[m_] := u[m] = Flatten[Table[s[k] - s[j], {k, 2, z1}, {j, 1, k - 1}]][[m]]
    Table[u[m], {m, 1, z1}]         (* A205371 *)
    v[n_, h_] := v[n, h] = If[IntegerQ[u[h]/n], h, 0]
    w[n_] := w[n] = Table[v[n, h], {h, 1, z1}]
    d[n_] := d[n] = First[Delete[w[n], Position[w[n], 0]]]
    Table[d[n], {n, 1, z2}]         (* A205441 *)
    k[n_] := k[n] = Floor[(3 + Sqrt[8 d[n] - 1])/2]
    m[n_] := m[n] = Floor[(-1 + Sqrt[8 n - 7])/2]
    j[n_] := j[n] = d[n] - m[d[n]] (m[d[n]] + 1)/2
    Table[k[n], {n, 1, z2}]         (* A205442 *)
    Table[j[n], {n, 1, z2}]         (* A205443 *)
    Table[s[k[n]], {n, 1, z2}]      (* A205444 *)
    Table[s[j[n]], {n, 1, z2}]      (* A205445 *)
    Table[s[k[n]] - s[j[n]], {n, 1, z2}]      (* A205446 *)
    Table[(s[k[n]] - s[j[n]])/n, {n, 1, z2}]  (* A205447 *)
Showing 1-2 of 2 results.