accident?
y.kohmoto
zbi74583 at boat.zero.ad.jp
Mon Jun 16 10:12:02 CEST 2003
I wonder why my sequence looks like A050354.
Is there any explanation about this phenomenon?
Yasutoshi
--------------------
ID Number: 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.See also: Cf. A025487, A050354.
Keywords: nonn,nice,easy,more
Offset: 1
Author(s): Yasutoshi Kohmoto (kohmoto(AT)z2.zzz.or.jp)
ID Number: A050354
Sequence: 1,1,1,3,1,5,1,9,3,5,1,21,1,5,5,27,1,21,1,21,5,5,1,81,3,5,9,
21,1,37,1,81,5,5,5,111,1,5,5,81,1,37,1,21,21,5,1,297,3,21,5,
21,1,81,5,81,5,5,1,201,1,5,21,243,5,37,1,21,5,37,1,513,1,5,
21,21,5,37,1,297,27,5,1,201
Name: Ordered factorizations of n with one level of parentheses.
Comments: a(n) depends only on prime signature of n (cf. A025487). So a(24)
=
a(375) since 24=2^3*3 and 375=3*5^3 both have prime signature
(3,1).
Formula: Dirichlet g.f.: (2-zeta(s))/(3-2*zeta(s)).
Example: 6=(6)=(3*2)=(2*3)=(3)*(2)=(2)*(3).
See also: Cf. A002033, A050351-A050359. a(p^k)=3^(k-1).
a(A002110)=A050351.Keywords: nonn
Offset: 1
Author(s): Christian G. Bower (bowerc(AT)usa.net), Oct 15 1999.
to Robert and Hugo :
Thanks for the extension for A083140.
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