prime signature
Christian G.Bower
bowerc at usa.net
Wed May 25 19:48:42 CEST 2005
------ Original Message ------
From: "kohmoto" <zbi74583 at boat.zero.ad.jp>
To: <seqfan at ext.jussieu.fr>
Subject: prime signature
> Hi, Mitch
> Here is an example of sequence which depends only on the prime signature
> but is not mutiplicative.
>
>
http://www.research.att.com/cgi-bin/access.cgi/as/njas/sequences/eisA.cgi?Anum=A051707
>
> I want to know the formula.
> I wish some one tell me it.
>
> Yasutoshi
>
>
ID Number: A051707
URL: http://www.research.att.com/projects/OEIS?Anum=A051707
Sequence: 1,1,1,3,1,5,1,8,3,5,1,21,1,5,5,23,1,21,1,21
Name: Number of factorizations of (n,n) into pairs (k,l).
Comments: Pairs (k,l) must satisfy 0<k, 0<l; if k=1 then l=1. Definition of
"*": (a,b)*(x,y)=(a*x,b*y); unit is (1,1).
a(n) depends only on prime signature of n
Example: (6,6)=(2,1)*(3,6)=(2,6)*(3,1)=(2,2)*(3,3)=(2,3)*(3*2), so
a(6)=5.
Can you better explain the definition of this sequence?
You have the line "if k=1 then l=1", which obviously isn't true
because the example has a (2,1) and a (3,1). Did you mean
"if k=1 then l not= 1" to exclude (1,1).
Also for each prime you have the value 1, yet a prime can be factored
into (p,p) and (1,p)*(p,1). Do you have a rule that excludes the latter?
Christian
More information about the SeqFan
mailing list