Number of cyclically symmetric plane partitions in the n-cube; also number of 2n X 2n half-turn symmetric alternating sign matrices divided by number of n X n alternating sign matrices.
A006366
Number of cyclically symmetric plane partitions in the n-cube; also number of 2n X 2n half-turn symmetric alternating sign matrices divided by number of n X n alternating sign matrices.
Terms
- a(0) =1a(1) =2a(2) =5a(3) =20a(4) =132a(5) =1452a(6) =26741a(7) =826540a(8) =42939620a(9) =3752922788a(10) =552176360205
External references
- oeis: A006366