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A272520 Number of set partitions of [n] into eight blocks with distinct sizes. 2

%I #4 May 01 2016 19:57:45

%S 73566121315513295589120000,302438498741554659644160000,

%T 2585849164240292339957568000,17681163441201479441398176000,

%U 144230432460463828639480320000,1126747392322972404668523840000,11096383744399962905356299840000,126335461333640259667975104096000

%N Number of set partitions of [n] into eight blocks with distinct sizes.

%H Alois P. Heinz, <a href="/A272520/b272520.txt">Table of n, a(n) for n = 36..1000</a>

%F a(n) = n! * [x^n*y^8] Product_{n>=1} (1+y*x^n/n!).

%p b:= proc(n, i, t) option remember; `if`(t>i or t*(t+1)/2>n

%p or t*(2*i+1-t)/2<n, 0, `if`(n=0, 1, b(n,i-1,t)+

%p `if`(i>n, 0, b(n-i, i-1, t-1)*binomial(n,i))))

%p end:

%p a:= n-> b(n$2, 8):

%p seq(a(n), n=36..45);

%Y Column k=8 of A131632.

%K nonn

%O 36,1

%A _Alois P. Heinz_, May 01 2016

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Last modified April 24 05:23 EDT 2024. Contains 371918 sequences. (Running on oeis4.)