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A249615
Number of non-singleton blocks in the n-th set partition (A231428).
2
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, 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, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3, 2, 2, 2
OFFSET
0,7
EXAMPLE
The 6th set partition has 2 non-singleton blocks {1,4} and {2,3}. So a(6) = 2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Tilman Piesk, Nov 02 2014
STATUS
approved