A tiny base-dependent formula for tetration (change-of-base?)
#3
Gottfried Wrote:....When rereading my article about "pascalmatrix tetrated" (*1) and playing/checking some computations, it came to my attention, that I already have a formula for sexp with fixed (integer) height parameter, but variable with the base. So feeding log(2) as parameter to the series may give 2^^3, and feeding log(3) gives then 3^^3 . In all my recent consideration the base-parameter was deeply calculated in the coefficients and the height-parameter was isolated and thus subject to change; here the height-parameter is hidden in the coefficients and the base-parameter is explicit and can be subject to change.

We need simply the first column of the tetrated pascalmatrix, scale it by reciprocal factorials and use it as coefficients for the powerseries:

\( {b\^\^}^h = \sum_{k=0}^{\infty} \frac{{P\^\^}^h_{k,0}}{k!}\log(b)^k \)
....

Gottfried,

Does your equation work for values of a,p > e^(1/e)?

Assuming it does, my next question would be does your equation need a \( b\^\^(h+\theta(h)) \) term?

Below is my base conversion equation, (which is more or less the same as Jay's earlier results), where n is an integer, so sexp(n) is always well defined and \( \theta(x) \) is a small 1-cyclic sinusoid transfer function, equal to zero for integers. \( \theta(x) \) is important if the desired sexp function is required to have all odd derivatives have positive values for all x>-2, otherwise the 5th order derivatives showed negative values. In my post, I tried to characterize \( \theta(x) \), where one base=e and the other base is a little larger than e^(1/e).

\( \text{sexp}_a(x + \theta(x)) =
\text{ } \lim_{n \to \infty}
\text{log}_a^{\circ n}(\text{sexp}_b (x + \text{slog}_b(\text{sexp}_a(n))) \)
Reply


Messages In This Thread
RE: A tiny base-dependent formula for tetration (change-of-base?) - by sheldonison - 03/16/2009, 01:36 PM

Possibly Related Threads…
Thread Author Replies Views Last Post
  Mixed-base tetration: five preprints, a faster fatou.gp fork, and a base-change calcu Lightrunner 0 585 07/15/2026, 08:33 AM
Last Post: Lightrunner
  Seeking an arXiv endorser for mixed-base tetration (math.DS) Lightrunner 0 399 07/13/2026, 10:19 PM
Last Post: Lightrunner
  [2sinh] exp(x) - exp( - (e-1) x), Low Base Constant (LBC) 1.5056377.. tommy1729 3 6,876 04/30/2023, 01:22 AM
Last Post: tommy1729
  f(x+y) g(f(x)f(y)) = f(x) + f(y) addition formula ? tommy1729 1 3,826 01/13/2023, 08:45 PM
Last Post: tommy1729
  Base -1 marraco 15 41,152 07/06/2022, 09:37 AM
Last Post: Catullus
  I thought I'd take a crack at base = 1/2 JmsNxn 9 16,363 06/20/2022, 08:28 AM
Last Post: Catullus
Question Formula for the Taylor Series for Tetration Catullus 8 15,925 06/12/2022, 07:32 AM
Last Post: JmsNxn
Big Grin Repetition of the last digits of a tetration of generic base Luknik 12 23,198 12/16/2021, 12:26 AM
Last Post: marcokrt
  On the [tex]2 \pi i[/tex]-periodic solution to tetration, base e JmsNxn 0 4,013 09/28/2021, 05:44 AM
Last Post: JmsNxn
  A different approach to the base-change method JmsNxn 0 4,383 03/17/2021, 11:15 PM
Last Post: JmsNxn



Users browsing this thread: 1 Guest(s)