A274645 Number of linear extensions of the one-level grid poset G[(2^n), (0^(n-1)), (0^(n-1))].

1, 20, 1301, 177260, 41385102, 14760468600, 7465847167005, 5083351577582300, 4483012419041095680, 4971032496120058085376, 6769339545226095791964160, 11105730970797793499164966912, 21604722570792867452576610648064

Offset

1,2

Comments

The definition of a one-level grid poset can be found in the Pan links. The number of linear extensions of the one-level grid poset G[(0^n), (0^(n-1)), (0^(n-1))] is given by the Catalan number A000108(n) and the number of linear extensions of the one-level grid poset G[(1^n), (0^(n-1)), (0^(n-1))] is given by A274644(n).

Links

Table of n, a(n) for n=1..13.

Ran Pan, Problem 1, Project P.

Ran Pan, Algorithmic Solution to Problem 1 (and linear extensions of general one-level grid-like posets), Project P.

Crossrefs

Cf. A000108, A274644.

Sequence in context: A153469 A160253 A338961 * A005982 A229476 A177597

Adjacent sequences: A274642 A274643 A274644 * A274646 A274647 A274648

Keyword

nonn

Author

Ran Pan, Jun 30 2016

Status

approved