cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A374896 Array read by falling antidiagonals: T(n,k) = denominator(Sum_{x>0} (x^n)/(k^x)); n >= 0 and k >= 2.

Original entry on oeis.org

1, 2, 1, 3, 4, 1, 4, 9, 2, 1, 5, 16, 27, 8, 1, 6, 25, 32, 27, 1, 1, 7, 36, 125, 128, 81, 4, 1, 8, 49, 27, 625, 128, 243, 4, 1, 9, 64, 343, 216, 3125, 512, 243, 16, 1, 10, 81, 256, 2401, 81, 3125, 1024, 729, 1, 1, 11, 100, 729, 2048, 16807, 972, 15625, 4096, 2187, 4, 1
Offset: 0

Views

Author

Mohammed Yaseen, Aug 03 2024

Keywords

Examples

			Array begins:
+-----+-----------------------------------------------+
| n\k |   2    3     4    5      6     7       8  ... |
+-----+-----------------------------------------------+
|  0  |   1    2     3    4      5     6       7  ... |
|  1  |   1    4     9   16     25    36      49  ... |
|  2  |   1    2    27   32    125    27     343  ... |
|  3  |   1    8    27  128    625   216    2401  ... |
|  4  |   1    1    81  128   3125    81   16807  ... |
|  5  |   1    4   243  512   3125   972  117649  ... |
|  6  |   1    4   243 1024  15625   486  823543  ... |
|  7  |   1   16   729 4096  78125 11664  823543  ... |
|  8  |   1    1  2187 2048 390625  2187 5764801  ... |
| ... | ...  ...   ...  ...    ...   ...     ...  ... |
+-----+-----------------------------------------------+
		

Crossrefs

Cf. A374895 (numerators).

Programs

  • PARI
    T(n,k) = denominator(polylog(-n, 1/k));
    matrix(7,7,n, k, T(n-1,k+1)) \\ Michel Marcus, Aug 04 2024

Formula

T(n,k) = denominator(polylog(-n, 1/k)).
T(n,k) = denominator(1/(k-1)^(n+1) * Sum_{m=1..n} A008292(n,m)*k^m).
T(0,k) = k-1.
T(1,k) = (k-1)^2.
T(2,k) = A277542(k-1).
T(n,2) = 1.
T(n,n) = A121985(n).
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