OFFSET
1,2
COMMENTS
Left border: A000005(n).
Row sums = 3 iff n-th row is prime.
EXAMPLE
First few rows of the triangle =
1;
2, 1;
2, 0, 1;
3, 3, 0, 1;
2, 0, 0, 0, 1;
4, 4, 4, 0, 0, 1;
2, 0, 0, 0, 0, 0, 1;
4, 7, 0, 5, 0, 0, 0, 1;
3, 0, 7, 0, 0, 0, 0, 0, 1;
4, 6, 0, 0, 6, 0, 0, 0, 0, 1;
2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
6, 12, 14, 11, 0, 7, 0, 0, 0, 0, 0, 1;
2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
4, 8, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 1;
...
MAPLE
A156837 := proc(n, k)
end proc: # R. J. Mathar, Mar 03 2013
CROSSREFS
KEYWORD
AUTHOR
Gary W. Adamson & Mats Granvik, Feb 16 2009
STATUS
approved