Number of permutations of 1..n with displacements restricted to {-7,-6,-5,-4,-3,-1,0,2}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =23a(6) =51a(7) =117a(8) =250a(9) =524a(10) =1123a(11) =2428a(12) =5274a(13) =11493a(14) =24927a(15) =54025a(16) =117003a(17) =253155a(18) =548139a(19) =1187354a(20) =2572374a(21) =5573514a(22) =12074638a(23) =26156163a(24) =56658896a(25) =122731402a(26) =265858041a(27) =575909407a(28) =1247556710a(29) =2702508126