Number of antichains (or order ideals) in the poset 4*m*n or plane partitions with at most m rows and n columns and entries <= 4.

A056940

Number of antichains (or order ideals) in the poset 4*m*n or plane partitions with at most m rows and n columns and entries <= 4.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =1a(6) =1a(7) =15a(8) =15a(9) =1a(10) =1a(11) =35a(12) =105a(13) =35a(14) =1a(15) =1a(16) =70a(17) =490a(18) =490a(19) =70a(20) =1a(21) =1a(22) =126a(23) =1764a(24) =4116a(25) =1764a(26) =126a(27) =1a(28) =1a(29) =210

External references