[seqfan] Re: Fw: COMMENT FROM submitA Zak Seidov A100836

[Max Alekseyev]

Here is an efficient PARI/GP procedure for computing terms of

{ A100836(n)=local(f,b,t,m); if(n==1,return(1)); if(n==2,return(3));
t=valuation(n,2); if(n==2^t, return(2^(2*t-1)-1)); f=factorint(n/2^t);
f=vector(matsize(f)[1],j,f[j,1]^(2*f[j,2]));
if(t>0,f=concat(f,[2^(2*t-1)])); b=n^2+1; forvec(v=vector(#f,i,[0,1]),
m=lift(chinese(vector(#f,j,Mod((-1)^v[j],f[j])))); if(m>1,
b=min(b,m));  ); b }

It computes first 10^5 terms of A100836 in less than 7 seconds on my PC.

Regards,
Max

On Thu, Nov 20, 2008 at 1:02 PM, zak seidov <zakseidov at yahoo.com> wrote:
> Anyone may wish to confirm/reject my corrected list,
> thx, zak
>
>
>
> --- On Thu, 11/20/08, The On-Line Encyclopedia of Integer Sequences <oeis at research.att.com> wrote:
>
>> From: The On-Line Encyclopedia of Integer Sequences <oeis at research.att.com>
>> Subject: COMMENT FROM submitA Zak Seidov A100836
>> To: njas at research.att.com
>> Cc: zakseidov at yahoo.com
>> Date: Thursday, November 20, 2008, 3:56 PM
>> The following is a copy of the email message that was sent
>> to njas
>> containing the comment you submitted.
>>
>> All greater than and less than signs have been replaced by
>> their html
>> equivalents.  They will be changed back when the message is
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>>
>> This copy is just for your records.  No reply is expected.
>>
>> %S A100836
>> 2,3,8,7,24,17,48,31,80,49,120,17,168,97,26,127,288,161,360,49,244,241,
>> %T A100836
>> 528,127,624,337,728,97,840,199,960,511,604,577,1126,161,1368,721,170,
>> %U A100836
>> 351,1680,197,1848,241,1376,1057,2208,127,2400,1249,2024,337,2808,1457
>> %E A100836 Terms corrected by Zak Seidov
>> (zakseidov(AT)yahoo.com), Nov 20 2008
>
>
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