Number of (n+2) X 1 arrays of occupancy after each element moves up to +-2 places but not 0 and without 2-loops.

A222160

Number of (n+2) X 1 arrays of occupancy after each element moves up to +-2 places but not 0 and without 2-loops.

Terms

    a(0) =1a(1) =5a(2) =17a(3) =53a(4) =159a(5) =467a(6) =1356a(7) =3913a(8) =11253a(9) =32299a(10) =92606a(11) =265353a(12) =760080a(13) =2176758a(14) =6233232a(15) =17847997a(16) =51103477a(17) =146319703a(18) =418938535a(19) =1199485661a(20) =3434300229a(21) =9832876386a(22) =28152852451a(23) =80605364957a(24) =230783807849a(25) =660764392260

External references