Number of zero-sum nX1 -2..2 arrays with every element equal to at least one horizontal or vertical neighbor.

A201884

Number of zero-sum nX1 -2..2 arrays with every element equal to at least one horizontal or vertical neighbor.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =5a(4) =1a(5) =23a(6) =25a(7) =97a(8) =155a(9) =553a(10) =893a(11) =2945a(12) =5721a(13) =16499a(14) =34509a(15) =96903a(16) =211929a(17) =571639a(18) =1310827a(19) =3446631a(20) =8106415a(21) =21036009a(22) =50484447a(23) =129556711a(24) =315618625a(25) =804915729a(26) =1980809241a(27) =5032086931a(28) =12478845269a(29) =31624865741

External references