A004248 Array read by ascending antidiagonals: A(n, k) = k^n.

1, 0, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 4, 3, 1, 0, 1, 8, 9, 4, 1, 0, 1, 16, 27, 16, 5, 1, 0, 1, 32, 81, 64, 25, 6, 1, 0, 1, 64, 243, 256, 125, 36, 7, 1, 0, 1, 128, 729, 1024, 625, 216, 49, 8, 1, 0, 1, 256, 2187, 4096, 3125, 1296, 343, 64, 9, 1, 0, 1, 512, 6561, 16384, 15625, 7776, 2401, 512, 81, 10, 1

Offset

0,9

Comments

This array transforms into A371761 using the Akiyama-Tanigawa algorithm for powers row by row. - Peter Luschny, Apr 16 2024

Links

T. D. Noe, Rows n=0..50 of triangle, flattened

Michelle Rudolph-Lilith, On the Product Representation of Number Sequences, with Application to the Fibonacci Family, arXiv preprint arXiv:1508.07894 [math.NT], 2015.

Formula

Table of x^y, where (x,y) = (0,0), (0,1), (1,0), (0,2), (1,1), (2,0), ...

As a number triangle, columns have g.f. x^k/(1 - kx). - Paul Barry, Mar 28 2005

From Paul Barry, Jul 13 2005: (Start)

T(n, k) = if(k <= n, k^(n - k), 0).

T(n, k) = Sum_{j=0..floor((n-k)/2)} (-1)^j*C(n-k, j)*C(n-k-j, n-k)*k^(n-k-2j).

(End)

Example

Seen as an array that is read by ascending antidiagonals:
[0] 1, 1,   1,    1,     1,     1,      1,      1,       1, ...
[1] 0, 1,   2,    3,     4,     5,      6,      7,       8, ...
[2] 0, 1,   4,    9,    16,    25,     36,     49,      64, ...
[3] 0, 1,   8,   27,    64,   125,    216,    343,     512, ...
[4] 0, 1,  16,   81,   256,   625,   1296,   2401,    4096, ...
[5] 0, 1,  32,  243,  1024,  3125,   7776,  16807,   32768, ...
[6] 0, 1,  64,  729,  4096, 15625,  46656, 117649,  262144, ...
[7] 0, 1, 128, 2187, 16384, 78125, 279936, 823543, 2097152, ...

Mathematica

T[x_, y_] := If[y == 0, 1, (x - y)^y];
Table[T[x, y], {x, 0, 11}, {y, x, 0, -1}] // Flatten (* Jean-François Alcover, Dec 15 2017 *)

Prog

(PARI)
T(x, y) = x^y \\ Charles R Greathouse IV, Feb 07 2017
(SageMath)
def Arow(n, len): return [k**n for k in range(len)]
for n in range(8): print([n], Arow(n, 9))  # Peter Luschny, Apr 16 2024

Crossrefs

For other versions see A051129 and A009998.

Row sums are A026898, diagonal sums are A104872. [Paul Barry, Mar 28 2005]

Cf. A003992, A048723, A371761.

Sequence in context: A361390 A369326 A369324 * A034373 A238889 A296207

Adjacent sequences: A004245 A004246 A004247 * A004249 A004250 A004251

Keyword

tabl,nonn,easy,nice,changed

Author

David W. Wilson

Extensions

New name by Peter Luschny, Apr 16 2024.

Status

approved