Number of (n+2) X 1 arrays of occupancy after each element moves up to +-2 places but not 0.

A222549

Number of (n+2) X 1 arrays of occupancy after each element moves up to +-2 places but not 0.

Terms

    a(0) =7a(1) =20a(2) =64a(3) =208a(4) =651a(5) =2056a(6) =6496a(7) =20483a(8) =64627a(9) =203905a(10) =643272a(11) =2029453a(12) =6402679a(13) =20199560a(14) =63726952a(15) =201050056a(16) =634285971a(17) =2001087460a(18) =6313163200a(19) =19917184799a(20) =62836052203a(21) =198239333473a(22) =625418559696

External references