A367443 a(n) is the number of free polyominoes that can be obtained from the polyomino with binary code A246521(n+1) by adding one cell.

1, 2, 4, 3, 9, 1, 5, 4, 3, 8, 6, 5, 11, 10, 10, 6, 6, 9, 5, 2, 4, 5, 11, 13, 11, 3, 12, 9, 11, 10, 11, 5, 11, 5, 11, 12, 11, 12, 5, 6, 10, 5, 13, 12, 12, 7, 6, 6, 7, 11, 11, 6, 11, 6, 5, 4, 12, 11, 11, 13, 12, 11, 12, 14, 13, 12, 6, 7, 11, 3, 11, 11, 10, 11

Offset

1,2

Comments

Can be read as an irregular triangle, whose m-th row contains A000105(m) terms, m >= 1.

Links

Pontus von Brömssen, Table of n, a(n) for n = 1..6473 (rows 1..10).

Index entries for sequences related to polyominoes.

Example

As an irregular triangle:
  1;
  2;
  4, 3;
  9, 1, 5,  4,  3;
  8, 6, 5, 11, 10, 10, 6, 6, 9, 5, 2, 4;
  ...
For n = 5, the L tetromino, whose binary code is A246521(5+1) = 15, can be extended to 9 different free pentominoes, so a(5) = 9. (All possible ways to add one cell lead to different pentominoes.)
For n = 6, the square tetromino, whose binary code is A246521(6+1) = 23, can only be extended to the P pentomino by adding one cell, so a(6) = 1.

Crossrefs

Cf. A000105, A246521, A255890 (row minima), A367126, A367439, A367441.

Sequence in context: A253791 A021045 A272471 * A155749 A198931 A344425

Adjacent sequences: A367440 A367441 A367442 * A367444 A367445 A367446

Keyword

nonn,tabf,changed

Author

Pontus von Brömssen, Nov 18 2023

Status

approved