Number of compositions of n that are neither strictly increasing nor weakly decreasing.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =2a(5) =7a(6) =18a(7) =45a(8) =101a(9) =219a(10) =461a(11) =957a(12) =1957a(13) =3978a(14) =8036a(15) =16182a(16) =32506a(17) =65202a(18) =130642a(19) =261601a(20) =523598a(21) =1047709a(22) =2096062a(23) =4192946a(24) =8386912a(25) =16775117a(26) =33551832a(27) =67105663a(28) =134213789a(29) =268430636