A274764 Number of linear extensions of the one-level grid poset G[(1^n), (1^(n-1)), (1^(n-1))].

1, 20, 962, 75080, 8133732, 1127589120, 190416834360, 37902843124640, 8686847271179984, 2252403871470920960, 651771144516905730048, 208193858907016903262208, 72758882836839703611703296, 27613191886304138293279719424, 11308972154842887758316960743424, 4971172331379604809443266242019328

Offset: 1

Author

Ran Pan, Jul 05 2016

Keywords

• nonn

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 Catalan number A000108(n), 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) and the number of linear extensions of the one-level grid poset G[(1^n), (1^(n-1)), (0^(n-1))] is given by A274763(n).

Links

• 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, A274763.