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.

A050172 Numbers k such that b(k) < b(k+1), where b = A050170.

Original entry on oeis.org

1, 2, 3, 5, 6, 8, 9, 11, 13, 14, 16, 18, 21, 22, 24, 25, 27, 30, 31, 33, 34, 36, 39, 40, 42, 45, 46, 48, 49, 51, 54, 55, 57, 59, 62, 63, 65, 68, 71, 72, 74, 75, 77, 79, 82, 83, 85, 86, 88, 91, 92, 94, 96, 99, 101, 104, 106, 107, 109, 110
Offset: 1

Views

Author

Clark Kimberling

Keywords

Comments

Complement of A050173.

Links

Programs

  • Mathematica
    kmax = 110;(* b = A050170 *) b[1] = 1; b[n_] := b[n] = If[FreeQ[Join[{0}, Array[b, n - 1]], f = Floor[b[n - 1]/Sqrt[5]]], f, Floor[b[n - 1]*Sqrt[5]]]; Reap[For[k = 1, k <= kmax, k++, If[b[k] < b[k + 1], Sow[k]]]][[2, 1]] (* Jean-François Alcover, Sep 12 2017 *)

A050173 Numbers k such that A050170(k) > A050170(k+1).

Original entry on oeis.org

4, 7, 10, 12, 15, 17, 19, 20, 23, 26, 28, 29, 32, 35, 37, 38, 41, 43, 44, 47, 50, 52, 53, 56, 58, 60, 61, 64, 66, 67, 69, 70, 73, 76, 78, 80, 81, 84, 87, 89, 90, 93, 95, 97, 98, 100, 102, 103, 105, 108, 111, 113, 114, 116, 119, 121, 124
Offset: 1

Views

Author

Clark Kimberling

Keywords

Comments

Complement of A050172.

Links

Crossrefs

Cf. A050170, A050172.

Programs

  • Mathematica
    kmax = 124; (* b = A050170 *) b[1] = 1; b[n_] := b[n] = If[FreeQ[Join[{0}, Array[b, n - 1]], f = Floor[b[n - 1]/Sqrt[5]]], f, Floor[b[n - 1]*Sqrt[5]]]; Reap[For[k = 1, k <= kmax, k++, If[b[k] > b[k + 1], Sow[k]]]][[2, 1]] (* Jean-François Alcover, Sep 12 2017 *)

A050171 a(n)=least k satisfying a(k)=n in A050170.

Original entry on oeis.org

1, 2, 5, 3, 8, 6, 21, 4, 13, 11, 9, 30, 7, 24, 22, 71, 20, 18, 16, 14, 45, 12, 39, 10, 33, 31, 106, 104, 29, 27, 25, 82, 23, 74, 72, 251, 249, 70, 68, 19, 62, 17, 54, 15, 48, 46, 163, 161, 44, 42, 40, 139, 38, 36, 34, 117, 115, 32, 109, 107, 366, 105
Offset: 1

Views

Author

Clark Kimberling

Keywords

Links

Programs

  • Mathematica
    terms = 62; (* b = A050170 *) b[1] = 1; b[n_] := b[n] = If[FreeQ[Join[{0}, Array[b, n-1]], f = Floor[b[n-1]/Sqrt[5]]], f, Floor[b[n-1]*Sqrt[5]]]; Table[FirstPosition[Array[b, 6*terms], n], {n, 1, terms}] // Flatten (* Jean-François Alcover, Sep 12 2017 *)

Extensions

Missing terms inserted by Jean-François Alcover, Sep 12 2017

A050416 a(1)=a(2)=1, then a(n+1) = floor(a(n)/3) if this is not among 0, a(1), ..., a(n); otherwise a(n+1) = a(n) + a(n-1).

Original entry on oeis.org

1, 1, 2, 3, 5, 8, 13, 4, 17, 21, 7, 28, 9, 37, 12, 49, 16, 65, 81, 27, 108, 36, 144, 48, 192, 64, 256, 85, 341, 113, 454, 151, 50, 201, 67, 22, 89, 29, 118, 39, 157, 52, 209, 69, 23, 92, 30, 10, 40, 50, 90, 140, 46, 15, 61, 20, 6, 26, 32
Offset: 1

Views

Author

Clark Kimberling

Keywords

Comments

Numbers appearing among the terms more than once include 1, 50, 265, 341, 516, 570, 622, ... - Ivan Neretin, Sep 04 2015

Links

Crossrefs

Cf. A050417.
Cf. A050000, A050004, A050076, A050080, A050084, A050104, A050124, A050128, A050132, A050135, A050136, A050137, A050138, A050139, A050170, A050196.

Programs

  • Mathematica
    a = {0, 1, 1}; Do[AppendTo[a, If[MemberQ[a, c = Quotient[a[[-1]], 3]], a[[-1]] + a[[-2]], c]], {n, 3, 59}]; Delete[a, 1] (* Ivan Neretin, Sep 04 2015 *)
Showing 1-4 of 4 results.

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