A045631 Number of 2n-bead black-white reversible complementable strings with n black beads and fundamental period 2n.

1, 1, 2, 6, 20, 70, 243, 889, 3276, 12276, 46435, 176869, 677022, 2602197, 10033212, 38787495, 150286400, 583434322, 2268848988, 8836447021, 34461894010, 134564992002, 526025788992, 2058359779051, 8061905110548, 31602659997975

Offset: 0

Author

David W. Wilson

Keywords

• nonn

Formula

Moebius transform of A045723 (Christian Bower).