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A048083
Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n+3)/3.
0
0, 0, 0, 2, 6, 9, 21, 45, 70, 154, 322, 525, 1125, 2325, 3921, 8301, 17061, 29491, 61915, 126763, 223210, 465746, 950818, 1698453, 3527109, 7184421, 12981421, 26855641, 54604081, 99589963, 205390163, 416990563, 766466053, 1576646941
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OFFSET
1,4
LINKS
Table of n, a(n) for n=1..34.
CROSSREFS
Sequence in context:
A391039
A047161
A318193
*
A127931
A346673
A077237
Adjacent sequences:
A048080
A048081
A048082
*
A048084
A048085
A048086
KEYWORD
nonn
AUTHOR
Clark Kimberling
STATUS
approved