Talk:Recamán's sequence

Computational complexity

The article says that the computational complexity is $a_{n}$ is $O(n^{2})$. This is true in the sense that it is an upper bound, but it is not a good upper bound. The reference is to a blog, in which the program uses an inefficient way to tell if a number has appeared previously in the sequence. Bubba73 ^{You talkin' to me?} 19:25, 14 December 2019 (UTC)

I removed this:

The computational complexity of the calculation of n-th term $a_{n}$ is $O(n^{2})$.

from the Complexity section, after discussion on the Math Project talk page (see Wikipedia_talk:WikiProject_Mathematics#Recamán's_sequence). It is a little misleading and is based on a poor implementation of checking to see if a number has appeared in the sequence before. Bubba73 ^{You talkin' to me?} 23:26, 14 December 2019 (UTC)

References

Definition

In the Definition, the word "it" appears twice, and the antecedent is not clear. Does "it" mean $n-1$? Or $a_{n-1}$? Surely not $a_{n}$? Mgnbar (talk) 02:47, 21 December 2019 (UTC)

I've changed it - see if it is OK. Bubba73 ^{You talkin' to me?} 03:04, 21 December 2019 (UTC)

log-log or semi-log

I think this plot is actually log-log. The coordinates on the x-axis look strange, but they increase logarithmically. Bubba73 ^{You talkin' to me?} 02:23, 9 March 2020 (UTC)

Agreed, the x-axis is logarithmic. But the y-axis is not.

From Log–log_plot:

uses logarithmic scales on both the horizontal and vertical axes.

In the linked image:

• The increment between equally spaced labeled values on the horizontal axis is multiplicative, with a ratio of 1e50.
• The increment between equally spaced labeled values on the vertical axis is linear, with a difference of 100.

That makes it a semi-log plot:

From Semi-log_plot:

has one axis on a logarithmic scale, the other on a linear scale.

A zero label on the vertical axis is immediately telling. Log(0) is negative infinity. No (finite) logarithmic axis can have a value labeled zero.-72.71.131.75 (talk) 12:12, 10 March 2020 (UTC)

Anticipating purists and pedants, "Log(0) is negative infinity" is "wrong!" If you would like to expound for paragraphs with precise wording, go ahead. I had my fill of Wikipedian pedants in an exchange yesterday.-72.71.131.75 (talk) 13:08, 10 March 2020 (UTC)

• • The two axes are labeled in a different style, but both are logarithmic. The nth term of the function tends to be > n. The $10^{275}$th term is much larger than 800. In fact, the 287th term is 802, so the y-axis is logarithmic. The 0 on the y-axis represents $10^{0}$. The base-10 log of 1 is 0. Bubba73 ^{You talkin' to me?} 17:03, 10 March 2020 (UTC)

Revert my edit if it is actually a log-log plot. If so, the numbering on its vertical axis is misleading. The graph is missing text to describe what it is trying to show. Which axis represents what? And the "modified" in the upper-right corner is mysterious. I am done here.

-72.71.131.75 (talk) 03:57, 11 March 2020 (UTC)

I don't know what "modified" means either. Bubba73 ^{You talkin' to me?} 06:18, 11 March 2020 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion

The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:

• Recaman.mid

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 10:15, 9 November 2020 (UTC)

Conjecture

Seems like Sloane no longer believes that all the positive integers are in the sequence. He says in the comments "I conjecture that every number eventually appears - see A057167, A064227, A064228. - N. J. A. Sloane. That was written in 1991. Today I'm not so sure that every number appears. - N. J. A. Sloane, Feb 26 2017" in the page for Recaman's sequence https://oeis.org/A005132. 74.77.174.132 (talk) 14:23, 21 November 2023 (UTC)