A378382 Number of maximal chains in the poset of all binary words of length <= n, ordered by B covers A iff A_i <= B_{i+k} for all i in A and some k >= 0.

1, 1, 2, 5, 16, 57, 226, 961, 4376, 21041, 106534, 563961, 3112924, 17839993, 105907946, 649432673, 4105783696, 26706965985, 178466243662, 1223248786921, 8589272300516, 61708802126441, 453143009601682, 3397715981566545, 25990997059282456, 202666687407866257

Offset

0,3

Links

Table of n, a(n) for n=0..25.

Example

a(3) = 5:
 () < (0) < (0,0) < (0,0,0),
 () < (0) < (0,0) < (0,1),
 () < (0) < (0,0) < (1,0),
 () < (0) < (1) < (0,1),
 () < (0) < (1) < (1,0).

Prog

(Python)
def mchains(n, k): return # See A378588
def A378382_list(max_n): return mchains(max_n, 2)

Crossrefs

Cf. A034841, A143672, A282698, A317145, column k=2 of A378588, A378608.

Sequence in context: A197158 A188314 A114296 * A121689 A357580 A192635

Adjacent sequences: A378379 A378380 A378381 * A378383 A378384 A378385

Keyword

nonn

Author

John Tyler Rascoe, Nov 26 2024

Status

approved