Number of n X 1 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

A280309

Number of n X 1 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =9a(6) =34a(7) =124a(8) =432a(9) =1464a(10) =4848a(11) =15768a(12) =50528a(13) =159920a(14) =500832a(15) =1554304a(16) =4785664a(17) =14632704a(18) =44465664a(19) =134378112a(20) =404089344a(21) =1209699584a(22) =3606669824a(23) =10713166848a(24) =31713660928a(25) =93585811456a(26) =275367776256a(27) =808068888576

External references