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.

A229986 Decimal expansion of the upper limit of the convergents of the continued fraction [1, 1/3, 1/9, 1/27, ... ].

Original entry on oeis.org

3, 6, 6, 8, 0, 3, 4, 6, 5, 5, 6, 2, 7, 6, 8, 0, 7, 7, 6, 6, 6, 1, 4, 8, 5, 5, 7, 0, 4, 1, 6, 0, 1, 5, 5, 9, 1, 4, 6, 3, 6, 5, 4, 1, 4, 0, 6, 7, 5, 5, 7, 2, 1, 9, 8, 4, 9, 8, 0, 6, 6, 7, 4, 1, 0, 1, 2, 8, 8, 1, 1, 9, 5, 9, 1, 8, 5, 6, 1, 0, 2, 0, 3, 8, 4, 7
Offset: 1

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Author

Clark Kimberling, Oct 06 2013

Keywords

Comments

Since sum{3^(-k), k = 0,1,2,...} converges, the convergents of [1, 1/3, 1/9, 1/27, ... ] diverge, by the Seidel Convergence Theorem. However, the odd-numbered convergents converge, as do the even-numbered convergents. In the Example section, these limits are denoted by u and v.

Examples

			u = 1.119... = [1, 8, 2, 1, 242, 8, 1, 6560, 26, 1, 177146, 80, 1,...];
v = 3.668... = [3, 1, 2, 80, 1, 8, 2186, 1, 26, 59048, 1, 80, ...].
In both cases, every term of the continued fraction has the form 3^m - 1.
		

Crossrefs

Programs

  • Mathematica
    $MaxExtraPrecision = Infinity; z = 500; t = Table[3^(-n), {n, 0, z}]; u = N[Convergents[t][[z - 1]], 120]; v = N[Convergents[t][[z]], 120];
    RealDigits[u] (* A229985 *)
    RealDigits[v] (* A229986 *)