[seqfan] Re: Digits of Pi in A179103 and A179104

Ray Chandler rayjchandler at sbcglobal.net
Wed Jul 7 00:29:20 CEST 2010

```The Mma code for A179103 and A179104 were copied from A119505 and modified
to produce the two subject sequences.

Prepending 3 to the digits of Pi was a mechanism to map 0th digit to 10th
digit in the first program, but serves no purpose in the following two
programs since the positive offsets make all the terms well-defined anyway.

Note that in the original program, the final table runs from 1 to 105 but
both new programs start with 0.  I think they both should begin with index 1
and produce the following results:

A179103

id = RealDigits[Pi, 10, 130][[1]];
Table[id[[17 + id[[n]]]], {n, 105}]

{4, 3, 6, 3, 2, 3, 8, 6, 2, 4, 2, 3, 3, 4, 3, 4, 8, 4, 3, 6, 6, 8, 6, \
6, 4, 4, 3, 4, 8, 4, 3, 2, 2, 8, 3, 3, 6, 3, 3, 4, 3, 6, 3, 4, 3, 3, \
4, 4, 2, 3, 2, 2, 3, 8, 2, 3, 4, 6, 3, 6, 6, 2, 3, 8, 4, 2, 4, 3, 3, \
6, 6, 2, 6, 8, 3, 6, 8, 2, 3, 3, 3, 3, 6, 8, 3, 2, 4, 6, 3, 8, 2, 4, \
6, 8, 3, 3, 4, 2, 6, 4, 3, 3, 8, 3, 6}

A179104

id = RealDigits[Pi, 10, 130][[1]];
Table[id[[23 + id[[n]]]], {n, 105}]

{3, 4, 8, 4, 3, 5, 3, 2, 3, 3, 3, 9, 5, 7, 5, 3, 3, 3, 9, 8, 2, 3, 2, \
8, 3, 3, 9, 3, 3, 7, 5, 3, 6, 3, 9, 9, 8, 4, 5, 7, 4, 2, 5, 3, 5, 5, \
3, 7, 3, 4, 6, 3, 9, 3, 6, 5, 7, 8, 5, 8, 8, 3, 5, 3, 3, 6, 7, 9, 4, \
2, 8, 6, 2, 3, 9, 2, 3, 6, 9, 5, 5, 9, 2, 3, 9, 6, 3, 8, 9, 3, 3, 3, \
8, 3, 4, 4, 7, 6, 2, 7, 5, 9, 3, 4, 8}

Ray Chandler

> -----Original Message-----
> From: seqfan-bounces at list.seqfan.eu
> [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Charles Greathouse
> Sent: Tuesday, July 06, 2010 4:51 PM
> To: Sequence Fanatics Discussion list
> Subject: [seqfan] Re: Digits of Pi in A179103 and A179104
>
> I think the entries should be edited, but I'm not entirely
> sure what should be done.  As a start, DigitsPi was unclear
> to me on my first reading.  Also, the brackets are
> inconsistent, and I don't like the artificial starting digit
> (unless the sequence is changed to "... of pi + 30").
>
> I don't understand the broader context in which having 8 is
> significant; maybe a comment is in order, or at least a cross-ref.
>
> Oh, and both sequences need ,base, and should have a space in
> "8:a(n)".
>
> Charles Greathouse
> Analyst/Programmer
> Case Western Reserve University
>
> On Tue, Jul 6, 2010 at 5:13 PM, N. J. A. Sloane
> <njas at research.att.com> wrote:
> > I can see that my editing of the definition of A179104
> destroyed the
> > motivation for the entry. I'm sorry. I will restore the
> original definition, which was:
> >
> > %N A179104 An offset of A119505 that gives a limited digit
> set {2, 3,
> > 4, 5, 6, 7, 8, 9} that in\ cludes 8:a(n)=DigitsPi[23+DigitsPi(n))
> >
> > Also, the original values, as submitted, were
> >
> > %S A179104
> >
> 4,4,3,6,3,2,3,8,6,2,4,2,3,3,4,3,4,8,4,3,6,6,8,6,6,4,4,3,4,8,4,3,2,2,8,
> > %T A179104
> >
> 3,3,6,3,3,4,3,6,3,4,3,3,4,4,2,3,2,2,3,8,2,3,4,6,3,6,6,2,3,8,4,2,4,3,3,
> > %U A179104
> >
> 6,6,2,6,8,3,6,8,2,3,3,3,3,6,8,3,2,4,6,3,8,2,4,6,8,3,3,4,2,6,4,3,3,8,3
> > (as Richard pointed out, these were wrong)
> >
> > Alexander Povolotsky sent me corrected values on Jul 05, namely:
> >
> > %S A179104 3,3,4,8,4,3,5,3,2,3,3,3,9,5,7,5,3,3,3,9,8,2,3,2,8,3,
> > %T A179104 3,9,3,3,7,5,3,6,3,9,9,8,4,5,7,4,2,5,3,5,5,3,7,3,4,6,
> > %U A179104 3,9,3,6,5,7,8,5,8,8,3,5,3,3,6,7,9,4,2,8,6,2,3,9,2,3
> >
> > which I put in plce yesterday.
> >
> > So the next version of the OEIS will have the corrected
> terms and the
> > original definitions.
> >
> > Having said that, I am still worried by the artificial
> insertion of 3
> > at the start of the decimal expansion of Pi!
> >
> > I will mark both entries as "unedited".
> >
> > Neil
> >

```