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

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =8a(5) =22a(6) =46a(7) =85a(8) =168a(9) =350a(10) =776a(11) =1787a(12) =3851a(13) =8141a(14) =17247a(15) =36921a(16) =79637a(17) =172237a(18) =371343a(19) =797047a(20) =1710188a(21) =3673435a(22) =7899653a(23) =16995309a(24) =36552835a(25) =78580754a(26) =168899252a(27) =363064232a(28) =780553896a(29) =1678245531