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 1-2 of 2 results.

A376354 Numbers that end in 0 when written in base of triangular numbers (cf. A000462).

Original entry on oeis.org

3, 6, 9, 10, 13, 15, 18, 21, 24, 27, 28, 31, 34, 36, 39, 42, 45, 48, 51, 54, 55, 58, 61, 64, 65, 66, 69, 72, 75, 76, 78, 81, 84, 87, 88, 91, 94, 97, 100, 101, 104, 105, 108, 111, 114, 115, 118, 120, 123, 126, 129, 130, 133, 135, 136, 139, 142, 145, 146, 149
Offset: 1

Views

Author

Clark Kimberling, Sep 22 2024

Keywords

Comments

Every positive integer is in exactly one of the following sequences: this sequence, A376355, or A376356.
Conjecture: {a(n+1) - a(n) : n >= 1} = {1, 2, 3}. (See related conjectures at A376355 and A376356.)

Crossrefs

Programs

  • Mathematica
    a[n_, poly_] := FromDigits[FoldList[{Mod[#[[1]], #2], Quotient[#[[1]], #2]} &, {n, 0}, Reverse[Map[(poly - 2)  #  (# - 1)/2 + # &, Range[Floor[Sqrt[2  n]]]]]][[All, 2]]]
    t3 = Map[a[#, 3] &, Range[200]]; (* A000462 *)
    m = Mod[t3, 10]
    Table[Flatten[Position[m, r]], {r, 0, 2}]
    p0 = Flatten[Position[m, 0]]  (* this sequence *)
    p1 = Flatten[Position[m, 1]]  (* A376355 *)
    p2 = Flatten[Position[m, 2]]  (* A376356 *)
    (* Peter J. C. Moses, Sep 20 2024 *)

A376355 Numbers that end in 1 when written in base of triangular numbers (cf. A000462).

Original entry on oeis.org

1, 4, 7, 11, 14, 16, 19, 22, 25, 29, 32, 35, 37, 40, 43, 46, 49, 52, 56, 59, 62, 67, 70, 73, 77, 79, 82, 85, 89, 92, 95, 98, 102, 106, 109, 112, 116, 119, 121, 124, 127, 131, 134, 137, 140, 143, 147, 150, 152, 154, 157, 160, 164, 167, 169, 172, 175, 178, 182
Offset: 1

Views

Author

Clark Kimberling, Sep 22 2024

Keywords

Comments

Every positive integer is in exactly one of the following sequences: A376355, this sequence, or A376356.
Conjecture: {a(n+1) - a(n) : n >= 1} = {2,3,4,5,6}. (See related conjectures at A376354 and A376356.)

Crossrefs

Programs

  • Mathematica
    a[n_, poly_] := FromDigits[FoldList[{Mod[#[[1]], #2], Quotient[#[[1]], #2]} &, {n, 0}, Reverse[Map[(poly - 2)  #  (# - 1)/2 + # &, Range[Floor[Sqrt[2  n]]]]]][[All, 2]]]
    t3 = Map[a[#, 3] &, Range[200]]; (* A000462 *)
    m = Mod[t3, 10]
    Table[Flatten[Position[m, r]], {r, 0, 2}]
    p0 = Flatten[Position[m, 0]]  (* A376354 *)
    p1 = Flatten[Position[m, 1]]  (* this sequence *)
    p2 = Flatten[Position[m, 2]]  (* A376356 *)
    (* Peter J. C. Moses, Sep 20 2024 *)
Showing 1-2 of 2 results.