OFFSET
1,2
COMMENTS
Row sums = n, left column = d(n), (A000005: 1, 2, 2, 3, 2, 4, 2, ...).
FORMULA
Inverse Moebius transform of A054521.
EXAMPLE
First few rows of the triangle:
1;
2, 0;
2, 1, 0;
3, 0, 1, 0;
2, 1, 1, 1, 0;
4, 1, 0, 0, 1, 0;
2, 1, 1, 1, 1, 1, 0;
4, 0, 2, 0, 1, 0, 1, 0;
3, 2, 0, 1, 1, 0, 1, 1, 0;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Jan 12 2007
EXTENSIONS
Definition clarified, a(56) corrected and more terms from Georg Fischer, May 29 2023
STATUS
approved