Number of set partitions of {1, ..., n} that avoid enhanced 3-crossings (or enhanced 3-nestings).

A108307

Number of set partitions of {1, ..., n} that avoid enhanced 3-crossings (or enhanced 3-nestings).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =51a(6) =191a(7) =772a(8) =3320a(9) =15032a(10) =71084a(11) =348889a(12) =1768483a(13) =9220655a(14) =49286863a(15) =269346822a(16) =1501400222a(17) =8519796094a(18) =49133373040a(19) =287544553912

External references