Third-order Bell numbers.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =119a(6) =700a(7) =4748a(8) =36403a(9) =310851a(10) =2922606a(11) =29977587a(12) =332929492a(13) =3978258079a(14) =50872884285a(15) =692985674373