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

Terms

a(0) =0a(1) =0a(2) =2a(3) =3a(4) =12a(5) =23a(6) =61a(7) =135a(8) =306a(9) =679a(10) =1496a(11) =3245a(12) =7013a(13) =15045a(14) =32108a(15) =68201a(16) =144297a(17) =304227a(18) =639461a(19) =1340353a(20) =2802566a(21) =5846953a(22) =12173864a(23) =25300472a(24) =52492698a(25) =108742226a(26) =224946169a(27) =464714125a(28) =958872587a(29) =1976242406