[seqfan] Re: invasion of third rate programs

zak seidov zakseidov at yahoo.com
Wed Dec 19 06:43:06 CET 2018


m = 8; is(n) = factor(n)[, 2]~ == vector(m, x, 1)
Is this good/fast enough?
Zak
 

    On Wednesday, December 19, 2018, 5:57:42 AM GMT+2, Frank Adams-watters via SeqFan <seqfan at list.seqfan.eu> wrote:  
 
 is(n) = omega(n)==8 && issquarefree(n) would also work. These (Hugo's or mine) aren't really all that slow; only a small fraction of the values of n are factored twice, and the rest is negligible.

Franklin T. Adams-Watters


-----Original Message-----
From: Hugo Pfoertner <yae9911 at gmail.com>
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
Sent: Tue, Dec 18, 2018 11:38 am
Subject: [seqfan] Re: invasion of third rate programs


A123322:
(PARI) is(n)=omega(n)==8 && bigomega(n)==8
slow, but correct.


On Tue, Dec 18, 2018 at 5:51 PM Joerg Arndt <arndt at jjj.de> wrote:

> The Pari code is wrong, giving [256, 384, 576, 640, 864, 896, 960]
> when using select(is,vector(10^3,n,n)).
>
> I am way too tired to fix, so somebody please do the right thing.
>
> Best regards,   jj
>

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