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%I #13 May 05 2023 08:19:16
%S 1,2,3,4,4,5,5,5,6,6,6,6,6,6,7,7,7,7,7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,8,
%T 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
%U 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,10
%N Number of brackets in distinct sets with fewest possible elements
%H Alois P. Heinz, <a href="/A199769/b199769.txt">Table of n, a(n) for n = 1..11306</a>
%F a(n) = A198759(n+1) - A198759(n).
%e There are three repetitions of 5 because of the sets {{{{{}}}}}, {{{}, {{}}}}, and {{{{}}}, {}}.
%p b:= proc(n) a(n):= `if`(n<2, n, add(a(n-k)*add(b(d)*d*
%p (-1)^(k/d+1), d=numtheory[divisors](k)), k=1..n-1)/(n-1))
%p end:
%p T:= n-> n$b(n):
%p seq(T(n), n=1..10); # _Alois P. Heinz_, May 05 2023
%Y Differences of A198759. Also n repeated A004111(n) times.
%K nonn
%O 1,2
%A _Joshua Zucker_, Nov 10 2011
%E Second set in example corrected by _Rick L. Shepherd_, May 22 2013
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