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 1-1 of 1 results.

A264201 Numerator of sum of numbers in set g(n) generated as in Comments.

Original entry on oeis.org

0, 1, 7, 46, 265, 1519, 8560, 47578, 264076, 1461439, 8075011, 44596708, 246189961, 1358762089, 7498499272, 41378660380, 228330571360, 1259923712821, 6952163820391, 38361311420962, 211673092313329, 1167984733037851, 6444783128779528, 35561432547881926
Offset: 0

Views

Author

Clark Kimberling, Nov 09 2015

Keywords

Comments

Starting with g(0) = {0}, generate g(n) for n > 0 inductively using these rules:
(1) if x is in g(n-1), then x + 1 is in g(n); and
(2) if x is in g(n-1) and x < 3, then x/3 is in g(n).
The sum of numbers in g(n) is a(n)/3^(n-1).

Examples

			g(0) = {0}, sum = 0.
g(1) = {1}, sum = 1.
g(2) = {1/3,2/1}, sum = 7/3.
g(3) = {1/9,2/3,4/3,3/1}, sum = 46/9.
		

Crossrefs

Cf. A264200.

Programs

  • Mathematica
    z = 5; x = 1/3;  g[0] = {0}; g[1] = {1};
    g[n_] := g[n] = Union[1 + g[n - 1], (1/3) Select[g[n - 1], # < 3 &]]
    Table[g[n], {n, 0, z}]
    Table[Total[g[n]], {n, 0, z}]
    u = Numerator[Table[Total[g[n]], {n, 0, z}] ]

Formula

Conjecture: a(n) = 4*a(n-1) + 9*a(n-2) + 18*a(n-3) - 81*a(n-4) - 162*a(n-5) - 243*a(n-6).
Showing 1-1 of 1 results.