Number of reversible strings with n-1 black beads and n-1 white beads. String is not palindromic.

A032095

Number of reversible strings with n-1 black beads and n-1 white beads. String is not palindromic.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =10a(4) =32a(5) =126a(6) =452a(7) =1716a(8) =6400a(9) =24310a(10) =92252a(11) =352716a(12) =1351616a(13) =5200300a(14) =20056584a(15) =77558760a(16) =300533760a(17) =1166803110a(18) =4537543340a(19) =17672631900a(20) =68923172032a(21) =269128937220

External references