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).
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
KEYWORD
nonn,tabf
AUTHOR
Pontus von Brömssen, Nov 18 2023
STATUS
approved