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%I #11 Nov 28 2014 22:18:49
%S 0,1,1,1,1,1,2,1,2,1,1,2,1,1,1,1,2,2,2,2,1,2,2,2,2,1,2,1,2,2,2,2,1,2,
%T 1,2,1,1,2,2,2,2,1,2,1,2,1,1,2,1,1,1,1,2,2,2,2,2,3,2,3,2,2,3,2,2,2,1,
%U 2,2,2,2,2,3,2,3,2,2,3,2,2,2
%N Number of non-singleton blocks in the n-th set partition (A231428).
%H Tilman Piesk, <a href="/A249615/b249615.txt">Table of n, a(n) for n = 0..9999</a>
%H Tilman Piesk, <a href="https://commons.wikimedia.org/wiki/File:Set_partitions_5;_list.svg">Illustrated list of the first 52 equivalence relations</a>
%H Tilman Piesk, <a href="https://en.wikiversity.org/wiki/Permutations_and_partitions_in_the_OEIS">Permutations and partitions in the OEIS</a> (Wikiversity)
%e The 6th set partition has 2 non-singleton blocks {1,4} and {2,3}. So a(6) = 2.
%Y Cf. A231428, A249616
%K nonn
%O 0,7
%A _Tilman Piesk_, Nov 02 2014