Number of LL's in all skew Dyck paths of semilength n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =7a(5) =38a(6) =192a(7) =946a(8) =4616a(9) =22440a(10) =108964a(11) =529133a(12) =2571079a(13) =12504038a(14) =60872038a(15) =296641049a(16) =1447054867a(17) =7065841496a(18) =34534088328a(19) =168933369259a(20) =827073303197