Number of compositions of n where the difference between largest and smallest parts equals one.

Terms

a(0) =0a(1) =0a(2) =2a(3) =3a(4) =9a(5) =11a(6) =25a(7) =35a(8) =60a(9) =96a(10) =157a(11) =241a(12) =401a(13) =637a(14) =1019a(15) =1639a(16) =2651a(17) =4258a(18) =6870a(19) =11075a(20) =17891a(21) =28895a(22) =46678a(23) =75412a(24) =121915a(25) =197109a(26) =318724a(27) =515414a(28) =833590a(29) =1348301