OFFSET
1,4
EXAMPLE
a(9) = 8 subsets: {2}, {4}, {6}, {8}, {1, 3, 5, 8, 9}, {3, 4, 5, 7, 9}, {1, 3, 5, 6, 8, 9} and {3, 4, 5, 6, 7, 9}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 27 2022
EXTENSIONS
a(24)-a(41) from Alois P. Heinz, Sep 27 2022
STATUS
approved