Number of compositions with alternating parts weakly decreasing (or weakly increasing).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =12a(6) =20a(7) =32a(8) =51a(9) =79a(10) =121a(11) =182a(12) =272a(13) =399a(14) =582a(15) =839a(16) =1200a(17) =1700a(18) =2394a(19) =3342a(20) =4640a(21) =6397a(22) =8771a(23) =11955a(24) =16217a(25) =21878a(26) =29386a(27) =39285a(28) =52301a(29) =69334