Integer part of Gamma(n+1/2)/Gamma(1/2).

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =6a(5) =29a(6) =162a(7) =1055a(8) =7918a(9) =67303a(10) =639383a(11) =6713530a(12) =77205601a(13) =965070017a(14) =13028445231a(15) =188912455860