# [seqfan] Re: Fwd: A nice (decimal) property of 78

David Wilson dwilson at gambitcomm.com
Fri Nov 7 20:41:54 CET 2008

```I was thinking more like

m, n numbers
x, y, z variables

sum                     x+y, x+y+z, x+10, 10+13 = 23
difference            x-y, x-y-z, x-10, 10-13 = -3
product               xy, xyz, 10x, 10*13 = (10)(13) = 130
Avoid x.y
real quotient        x/y, x/(y+z), x/(yz),
13x/10                               Be careful with grouping
integer quotient    x\y, x\(y+x), 100\17 = 5
floor                    floor(x), [x], [12] = 12, [3.14] = 3,
[-1.5] = -2 Prefer [x] over floor(x)
nth prime             p(x) = A000040(x), p_x, p25 = p_25 = p(25) = 97
prime index         pi(x), pi(11) = 5
numeral concatenation  x||y; 314||159 = 314159

I could go on, but you get the point. A glossary to define preferred
usage of symbols in OEIS.

N. J. A. Sloane wrote:
> Someone said:
>
>
> What would REALLY be convenient is for the OEIS to have an mathematical
> symbol glossary.
>
> Me:  I use the Index to the OEIS for that purpose.
>
> I can add more entries.
>
> Here is a typical entry:
>
> unitary phi (or unitary totient) function uphi: A047994
>
> Neil
>
>
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>
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>
>
>

```