OFFSET
1,2
FORMULA
Row sums = A127736: (1, 7, 21, 46, 85, 141, ...).
T(n,n) = n^2. T(n,k) = k*(n+1), 1<=k<n. - R. J. Mathar, Jul 21 2009
EXAMPLE
First few rows of the triangle are:
1;
3, 4;
4, 8, 9;
5, 10, 15, 16;
6, 12, 18, 24, 25;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Jan 26 2007
EXTENSIONS
A-number of left factor in the definition corrected by R. J. Mathar, Jul 21 2009
a(19) corrected and more terms from Georg Fischer, Jun 05 2023
STATUS
approved