# [seqfan] Re: Subsets with prime sums again - Part 2

zak seidov zakseidov at yahoo.com
Wed Oct 28 15:14:50 CET 2009

```
--- On Wed, 10/28/09, Christopher Gribble <chris.eveswell at virgin.net> wrote:

> From: Christopher Gribble <chris.eveswell at virgin.net>
> Subject: [seqfan]  Subsets with prime sums again - Part 2
> To: "'Sequence Fanatics Discussion list'" <seqfan at list.seqfan.eu>
> Date: Wednesday, October 28, 2009, 9:33 AM
> Here is another triangle whose column
> sums give Zak's sequence
>
> 4, 26, 444, 11998, 382716, 15844060, .
>
>
>
> This is related to the method of subset construction.
>
> For N = 2, the subsets are {1, 2}, {1, 4}, {2, 3}, {3, 4}.
>
> The first member is 1 in 2 subsets, 2 in 1 subset and 3 in
> 1 subset.
>

>             Frequency with
> which first
>
>             subset member
> values occur
>
> First   N   2
>   3      4
>
> Member
>
>  1          2
> 8    111
>
>  2          1
> 8     88
>
>  3          1
> 4     67
>
>  4
>    4     55
>
>  5
>    1     42
>
>  6
>    1     32
>
>  7
>        23
>
>  8
>        15
>
>  9
>         6
>
> 10
>         3
>
> 11
>         2

> Total       4
>    26    444

>
> This triangle is not in the OEIS either.
>
Christopher,
(as Neil just said)
Best,
Zak

> Best regards,
> Chris Gribble

```