login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A304991 a(n) = A000041(n) * A000009(n). 2

%I #6 May 23 2023 15:12:16

%S 1,1,2,6,10,21,44,75,132,240,420,672,1155,1818,2970,4752,7392,11286,

%T 17710,26460,40128,60192,89178,130520,192150,278036,401940,577920,

%U 825396,1168640,1658784,2326280,3256110,4544064,6302720,8706555,12008636,16444120,22476960

%N a(n) = A000041(n) * A000009(n).

%F a(n) ~ exp(Pi*(1+sqrt(2))*sqrt(n/3)) / (16*3^(3/4)*n^(7/4)).

%p b:= proc(n) option remember; `if`(n=0, 1, add(b(n-j)*add(

%p `if`(d::odd, d, 0), d=numtheory[divisors](j)), j=1..n)/n)

%p end:

%p a:= n-> b(n)*combinat[numbpart](n):

%p seq(a(n), n=0..40); # _Alois P. Heinz_, May 23 2023

%t Table[PartitionsP[n]*PartitionsQ[n], {n, 0, 50}]

%Y Cf. A000009, A000041, A015128.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, May 23 2018

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 6 11:05 EDT 2024. Contains 375712 sequences. (Running on oeis4.)