OFFSET
0,4
FORMULA
E.g.f. of column k: exp(x)*(exp((k-1)*x) - 1)/(k - 1).
E.g.f. of column k: 2*exp((k+1)*x/2)*sinh((k-1)*x/2)/(k - 1).
A(n, k) = Sum_{i=0..n-1} k^i.
EXAMPLE
The array begins:
0, 0, 0, 0, 0, ...
1, 1, 1, 1, 1, ...
3, 4, 5, 6, 7, ...
7, 13, 21, 31, 43, ...
15, 40, 85, 156, 259, ...
...
MATHEMATICA
A[n_, k_]:=(k^n-1)/(k-1); Flatten[Table[A[n-k+2, k], {n, 0, 10}, {k, 2, n+2}]]
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Stefano Spezia, Mar 13 2023
STATUS
approved