Number of inversion sequences avoiding pattern 120.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =23a(5) =103a(6) =515a(7) =2803a(8) =16334a(9) =100700a(10) =650905a(11) =4380595a(12) =30528410a(13) =219352058a(14) =1619260140a(15) =12245357074a(16) =94636062782a(17) =745907086918