# [seqfan] Re: A019303 "Pascal sweep" for k=2: draw a horizontal line ...

Neil Sloane njasloane at gmail.com
Fri Oct 12 17:26:36 CEST 2018

```actually I was a bit confused about where the line starts sweeping

let me start again:

I don't have a problem with the definition

draw a horizontal line through the 1 at C(2,0) in Pascal's triangle; rotate
this line and record the sum of the numbers on it (excluding the initial 1).

As the line starts rotating, the first time we hit some numbers is when the
line passes through C(2,0) = 1 (which we don't count), and C(3,3) = 1, for
a total of 1, the first term

When we rotate it a bit more, the next event is when we hit  C(3,2)=3, and
C(4,4) = 1, total is 3+1 = 4
When we rotate it a bit more, the next event is when we hit C(5,5) = 1, so
we get a total of 1
so far we have 1, 4, 1,

and so on

Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Email: njasloane at gmail.com

On Fri, Oct 12, 2018 at 11:18 AM Neil Sloane <njasloane at gmail.com> wrote:

> I don't have a problem with the definition
>
> draw a horizontal line through the 1 at C(2,0) in Pascal's triangle;
> rotate this line and record the sum of the numbers on it (excluding the
> initial 1).
>
> As the line starts rotating, the first time we hit some numbers is when
> the line passes through C(2,0) = 1 (which we don't count), C(3,2)=3, and
> C(4,4) = 1, total is 3+1 = 4
>
>
>
> When we rotate it a bit more, the next event is when we hit C(5,5) = 1, so
> we get a total of 1
>
> and so on
>
> Best regards
> Neil
>
> Neil J. A. Sloane, President, OEIS Foundation.
> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
> Email: njasloane at gmail.com
>
>
>
> On Fri, Oct 12, 2018 at 10:23 AM Georg.Fischer <georg.fischer at t-online.de>
> wrote:
>
>> Hello Seqfans,
>>
>> this sequence says nothing (Formula, comment, crossref.) but:
>>
>> A019303 "Pascal sweep" for k=2: draw a horizontal line through the 1 at
>> C(k,0) in Pascal's triangle; rotate this line and record the sum of the
>> numbers on it (excluding the initial 1).                0
>> 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 1, 10, 1, 11, 1, 12, 1, 13, 1, 14,
>> 1, 15, 1, 16, 1, 17, 1, 18, 1, 19, 1, 20, 1, 21, 1, 22, 1, 23, ...
>> OFFSET 0,2
>>
>> It seems to be a subsequence of:
>>
>> A179820         a(n) = n-th triangular number mod (n+2).
>> 0, 1, 3, 1, 4, 1, 5, 1, 6, 1, 7, 1,
>> OFFSET 0,3
>>
>> I wonder whether I'm the only one who does not understand
>> the name of A019303. I googled "Pascal sweep" - I seems
>> not to be a common term.
>>
>> Best regards - Georg
>>
>> --
>> Seqfan Mailing list - http://list.seqfan.eu/
>>
>

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