a(n) = binomial(prime(n+1)-1, prime(n)-1).

Terms

a(0) =2a(1) =6a(2) =15a(3) =210a(4) =66a(5) =1820a(6) =153a(7) =7315a(8) =376740a(9) =435a(10) =1947792a(11) =91390a(12) =861a(13) =163185a(14) =20358520a(15) =40475358a(16) =1770a(17) =90858768a(18) =916895a(19) =2556a(20) =256851595a(21) =1749060a(22) =541931236a(23) =132601016340a(24) =3921225a(25) =5151a(26) =4967690a(27) =5778a(28) =6210820a(30) =11358880