Naming of A178647

[Bruce L]

Hello,

This is my first post here, so my apologies if it is not appropriate. I had a question regarding the naming of https://oeis.org/A178647.

Currently, the sequence is called: "Decimal expansion of the fraction of a population falling within +- 1 standard deviation of the mean, assuming a normal distribution."

I thought it was odd that the title applies the constant to a population assuming normality. It seems simpler to state explicitly that the constant relates to the normal distribution, rather than applying it to a theoretical population in a roundabout way.

Could this be renamed for clarity, or is the name acceptable as it is?

[M F Hasler]

On Fri, May 29, 2026, 14:55 Bruce L <coconu...@gmail.com> wrote:

 https://oeis.org/A178647.: "Decimal expansion of the fraction of a population falling within +- 1 standard deviation of the mean, assuming a normal distribution."

I thought it was odd that the title applies the constant to a population assuming normality. It seems simpler to state explicitly that the constant relates to the normal distribution, rather than applying it to a theoretical population in a roundabout way.

Could this be renamed for clarity, or is the name acceptable as it is?

I agree. 

Also, it's not a fraction, but an irrational constant...

(whereas for any finite population, there's a finite number of individuals in the specified range and the mentioned fraction is a rational number depending on the size of the population ...

Of course, what is meant is the probability of lying within +-1sigma around the mean, for a normal distribution.)

I propose to name it " Decimal expansion of erf(1/sqrt(2)): ... "

and maybe leave some interpretation after that in the "NAME", and/or move it to COMMENTS.

(For search purposes, it may be useful to have keywords like "standard deviation", "normal distribution" in the name -- and for the same reason it may be useful to have "erf" in it.)

I think when there's a simple explicit definition, it should be preferred over the various possible interpretations or problems of which it is the solution.

- Maximilian

[Allan Wechsler]

I also note that OEIS does not contain the continued fraction of this constant (unless I made a mistake). I think this is 0, 1, 2, 6, 1, 1, 1, 1, 32, ...

-- Allan

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