A308698 Square array A(n,k), n >= 1, k >= 0, read by antidiagonals, where A(n,k) is Sum_{d|n} d^(k*d).
1, 1, 2, 1, 5, 2, 1, 17, 28, 3, 1, 65, 730, 261, 2, 1, 257, 19684, 65553, 3126, 4, 1, 1025, 531442, 16777281, 9765626, 46688, 2, 1, 4097, 14348908, 4294967553, 30517578126, 2176783082, 823544, 4, 1, 16385, 387420490, 1099511628801, 95367431640626, 101559956688164, 678223072850, 16777477, 3
Offset: 1
Examples
Square array begins: 1, 1, 1, 1, 1, ... 2, 5, 17, 65, 257, ... 2, 28, 730, 19684, 531442, ... 3, 261, 65553, 16777281, 4294967553, ... 2, 3126, 9765626, 30517578126, 95367431640626, ...
Links
- Seiichi Manyama, Antidiagonals n = 1..52, flattened
Crossrefs
Programs
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Mathematica
T[n_, k_] := DivisorSum[n, #^(k*#) &]; Table[T[k, n - k], {n, 1, 9}, {k, 1, n}] // Flatten (* Amiram Eldar, May 09 2021 *)
Formula
L.g.f. of column k: -log(Product_{j>=1} (1 - x^j)^(j^(k*j-1))).
G.f. of column k: Sum_{j>=1} j^(k*j) * x^j/(1 - x^j).