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A319278 Square array sigma_k(n) read down antidiagonals: sum of the k-th powers of the divisors of n. 1
1, 1, 3, 1, 5, 4, 1, 9, 10, 7, 1, 17, 28, 21, 6, 1, 33, 82, 73, 26, 12, 1, 65, 244, 273, 126, 50, 8, 1, 129, 730, 1057, 626, 252, 50, 15, 1, 257, 2188, 4161, 3126, 1394, 344, 85, 13, 1, 513, 6562, 16513, 15626, 8052, 2402, 585, 91, 18, 1, 1025, 19684, 65793, 78126, 47450, 16808, 4369, 757, 130, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Equals the square array A082771 without its first column.
LINKS
FORMULA
sigma_k(n) = sum_{d|n} d^k.
EXAMPLE
The array starts in row n=1 with columns k>=1 as:
1 1 1 1 1 1 1 1
3 5 9 17 33 65 129 257
4 10 28 82 244 730 2188 6562
7 21 73 273 1057 4161 16513 65793
6 26 126 626 3126 15626 78126 390626
12 50 252 1394 8052 47450 282252 1686434
8 50 344 2402 16808 117650 823544 5764802
15 85 585 4369 33825 266305 2113665 16843009
MATHEMATICA
T[n_, k_] := DivisorSigma[k, n];
Table[T[n-k+1, k], {n, 1, 11}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Dec 16 2021 *)
CROSSREFS
Cf. A082771, A023887 (diagonal), A319194 (partial column sums).
Sequence in context: A029655 A110813 A124883 * A294579 A308502 A308674
KEYWORD
nonn,tabl,easy
AUTHOR
R. J. Mathar, Sep 16 2018
STATUS
approved

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Last modified July 16 10:27 EDT 2024. Contains 374345 sequences. (Running on oeis4.)