login
A137679
Triangle read by rows, A000012 * A008284.
2
1, 2, 1, 3, 2, 1, 4, 4, 2, 1, 5, 6, 4, 2, 1, 6, 9, 7, 4, 2, 1, 7, 12, 11, 7, 4, 2, 1, 8, 16, 16, 12, 7, 4, 2, 1, 9, 20, 23, 18, 12, 7, 4, 2, 1, 10, 25, 31, 27, 19, 12, 7, 4, 2, 1, 11, 30, 41, 38, 29, 19, 12, 7, 4, 2, 1, 12, 36, 53, 53, 42, 30, 19, 12, 7, 4, 2, 1
OFFSET
1,2
COMMENTS
Row sums = A026905: (1, 3, 6, 11, 18, 29, ...).
Rows tend to A000070 starting from the right: (1, 2, 4, 7, 12, 19, 30, ...).
FORMULA
A000012 * A008284 as infinite lower triangular matrices.
EXAMPLE
First few rows of the triangle:
1;
2, 1;
3, 2, 1;
4, 4, 2, 1;
5, 6, 4, 2, 1;
6, 9, 7, 4, 2, 1;
7, 12, 11, 7, 4, 2, 1;
8, 16, 16, 12, 7, 4, 2, 1;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Feb 05 2008
EXTENSIONS
a(38) = 20 corrected by Georg Fischer, May 29 2023
STATUS
approved