A348455 Irregular triangle read by rows: T(n,k) (n >= 1, 1 <= k <= number of divisors of n^2) is the number of ways to tile an n X n chessboard with rook-connected polyominoes of area d_k, where d_k is the k-th divisor of n^2.

1, 1, 2, 1, 1, 10, 1, 1, 70, 117, 36, 1, 1, 4006, 1, 1, 6728, 80092, 178939, 451206, 442791, 264500, 80518, 1, 1, 158753814, 1

Offset

1,3

Comments

This is an essentially identical triangle to A348453, except that the data in each row has effectively been reversed. Rather than copying everything here, please refer to A348453 for further information.

Links

Table of n, a(n) for n=1..27.

Example

Triangle begins:
1,
1, 2, 1,
1, 10, 1,
1, 70, 117, 36, 1,
1, 4006, 1,
1, 6728, 80092, 178939, 451206, 442791, 264500, 80518, 1,
1, 158753814, 1,
1, ?, ?, 187497290034, ?, 7157114189, 1,
...

Crossrefs

Cf. A348452, A348453, A348454, A348456.

Cf. A048691 (row lengths).

Sequence in context: A054768 A104251 A320576 * A348453 A345748 A153731

Adjacent sequences: A348452 A348453 A348454 * A348456 A348457 A348458

Keyword

nonn,tabf,more

Author

N. J. A. Sloane, Oct 27 2021

Status

approved