Number of compositions of n that are neither unimodal nor is their negation.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =2a(7) =9a(8) =32a(9) =92a(10) =243a(11) =587a(12) =1361a(13) =3027a(14) =6564a(15) =13928a(16) =29127a(17) =60180a(18) =123300a(19) =250945a(20) =508326a(21) =1025977a(22) =2065437a(23) =4150056a(24) =8327344a(25) =16692844a(26) =33438984a(27) =66951671a(28) =134004892a(29) =268148573