Number of hooked Skolem sequences of order n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =0a(4) =0a(5) =38a(6) =124a(7) =0a(8) =0a(9) =12808a(10) =72648a(11) =0a(12) =0a(13) =21878816a(14) =168870048a(15) =0a(16) =0a(17) =113071735648a(19) =0a(20) =0