Number of permutations of zero-one words with A056576(n)-n zeros and n-1 ones.

Terms

a(0) =1a(1) =2a(2) =3a(3) =10a(4) =15a(5) =56a(6) =210a(7) =330a(8) =1287a(9) =2002a(10) =8008a(11) =31824a(12) =50388a(13) =203490a(14) =319770a(15) =1307504a(16) =2042975a(17) =8436285a(18) =34597290a(19) =54627300a(20) =225792840a(21) =354817320a(22) =1476337800a(23) =6107086800a(24) =9669554100a(25) =40225345056a(26) =63432274896a(27) =265182149218a(28) =416714805914