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.

Showing 1-2 of 2 results.

A308698 Square array A(n,k), n >= 1, k >= 0, read by antidiagonals, where A(n,k) is Sum_{d|n} d^(k*d).

Original entry on oeis.org

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

Views

Author

Seiichi Manyama, Jun 17 2019

Keywords

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, ...
		

Crossrefs

Columns k=0..3 give A000005, A062796, A308696, A308697.
Row n=1..2 give A000012, A052539.

Programs

  • 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).

A308701 Square array A(n,k), n >= 1, k >= 0, read by antidiagonals, where A(n,k) is Sum_{d|n} d^(k*(d-1)).

Original entry on oeis.org

1, 1, 2, 1, 3, 2, 1, 5, 10, 3, 1, 9, 82, 67, 2, 1, 17, 730, 4101, 626, 4, 1, 33, 6562, 262153, 390626, 7788, 2, 1, 65, 59050, 16777233, 244140626, 60466262, 117650, 4, 1, 129, 531442, 1073741857, 152587890626, 470184985314, 13841287202, 2097219, 3
Offset: 1

Views

Author

Seiichi Manyama, Jun 22 2019

Keywords

Examples

			Square array begins:
   1,   1,      1,         1,            1, ...
   2,   3,      5,         9,           17, ...
   2,  10,     82,       730,         6562, ...
   3,  67,   4101,    262153,     16777233, ...
   2, 626, 390626, 244140626, 152587890626, ...
		

Crossrefs

Columns k=0..2 give A000005, A262843, A308753.
Row n=1..3 give A000012, A000051, A062396.

Programs

  • Mathematica
    T[n_, k_] := DivisorSum[n, #^(k*(# - 1)) &]; 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-k-1))).
G.f. of column k: Sum_{j>=1} j^(k*(j-1)) * x^j/(1 - x^j).
Showing 1-2 of 2 results.