OFFSET
1,2
COMMENTS
T(n,k) = T(n,k-1) for k>A036234(n). The triangle contains all values of T up to the last element of each row that is different from its predecessor.
LINKS
Alois P. Heinz, Rows n = 1..200, flattened
FORMULA
EXAMPLE
T(5,3) = 21 because there are 21 nonempty subsets of {1,2,3,4,5} having <=3 pairwise coprime elements: {1}, {2}, {3}, {4}, {5}, {1,2}, {1,3}, {1,4}, {1,5}, {2,3}, {2,5}, {3,4}, {3,5}, {4,5}, {1,2,3}, {1,2,5}, {1,3,4}, {1,3,5}, {1,4,5}, {2,3,5}, {3,4,5}.
Irregular Triangle T(n,k) begins:
1;
2, 3;
3, 6, 7;
4, 9, 11;
5, 14, 21, 23;
6, 17, 25, 27;
7, 24, 43, 53, 55;
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Alois P. Heinz, Mar 07 2011
STATUS
approved