Number of extended Skolem sequences of order n.

Terms

a(0) =2a(1) =2a(2) =6a(3) =22a(4) =48a(5) =160a(6) =636a(7) =3556a(8) =19488a(9) =95872a(10) =594320a(11) =4459888a(12) =32131648a(13) =227072544a(14) =1875064880a(15) =17851780784a(16) =165367171136