login
A328807
Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where T(n,k) is Sum_{i=0..n} binomial(n,i)*Sum_{j=0..i} binomial(i,j)^k.
7
1, 1, 3, 1, 3, 8, 1, 3, 9, 20, 1, 3, 11, 27, 48, 1, 3, 15, 45, 81, 112, 1, 3, 23, 93, 195, 243, 256, 1, 3, 39, 225, 639, 873, 729, 576, 1, 3, 71, 597, 2583, 4653, 3989, 2187, 1280, 1, 3, 135, 1665, 11991, 32133, 35169, 18483, 6561, 2816
OFFSET
0,3
COMMENTS
T(n,k) is the constant term in the expansion of (1 + Product_{j=1..k-1} (1 + x_j) + Product_{j=1..k-1} (1 + 1/x_j))^n for k > 0.
For fixed k > 0 is T(n,k) ~ (2^k + 1)^(n + (k-1)/2) / (2^((k-1)^2/2) * sqrt(k) * (Pi*n)^((k-1)/2)). - Vaclav Kotesovec, Oct 28 2019
LINKS
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, ...
3, 3, 3, 3, 3, 3, ...
8, 9, 11, 15, 23, 39, ...
20, 27, 45, 93, 225, 597, ...
48, 81, 195, 639, 2583, 11991, ...
112, 243, 873, 4653, 32133, 260613, ...
MATHEMATICA
T[n_, k_] := Sum[Binomial[n, i] * Sum[Binomial[i, j]^k, {j, 0, i}], {i, 0, n}]; Table[T[k, n - k], {n, 0, 9}, {k, 0, n}] // Flatten (* Amiram Eldar, May 06 2021 *)
CROSSREFS
Columns k=0..5 give A001792, A000244, A026375, A002893, A328808, A328809.
Main diagonal gives A328810.
Sequence in context: A019603 A171843 A132476 * A103279 A208910 A209760
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Oct 28 2019
STATUS
approved