Half the number of n X 2 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

A185828

Half the number of n X 2 binary arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Terms

    a(0) =1a(1) =3a(2) =10a(3) =23a(4) =61a(5) =162a(6) =421a(7) =1103a(8) =2890a(9) =7563a(10) =19801a(11) =51842a(12) =135721a(13) =355323a(14) =930250a(15) =2435423a(16) =6376021a(17) =16692642a(18) =43701901a(19) =114413063a(20) =299537290a(21) =784198803a(22) =2053059121a(23) =5374978562a(24) =14071876561a(25) =36840651123a(26) =96450076810a(27) =252509579303

External references