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

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =10a(5) =20a(6) =46a(7) =90a(8) =185a(9) =374a(10) =810a(11) =1718a(12) =3565a(13) =7504a(14) =15668a(15) =32880a(16) =68748a(17) =144309a(18) =302723a(19) =633904a(20) =1328936a(21) =2784579a(22) =5837343a(23) =12232245a(24) =25638253a(25) =53738027a(26) =112620095a(27) =236040957a(28) =494698039a(29) =1036837512