Number of compositions of n whose run-lengths are not unimodal.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =3a(8) =8a(9) =28a(10) =74a(11) =188a(12) =468a(13) =1120a(14) =2596a(15) =5944a(16) =13324a(17) =29437a(18) =64288a(19) =138929a(20) =297442a(21) =632074a(22) =1333897a(23) =2798352a(24) =5840164a(25) =12132638a(26) =25102232a(27) =51750419a(28) =106346704a(29) =217921161