Number of 2 X n checkerboards (with at least one red square) in which the set of red squares is edge connected.

A059020

Number of 2 X n checkerboards (with at least one red square) in which the set of red squares is edge connected.

Terms

    a(0) =0a(1) =3a(2) =13a(3) =40a(4) =108a(5) =275a(6) =681a(7) =1664a(8) =4040a(9) =9779a(10) =23637a(11) =57096a(12) =137876a(13) =332899a(14) =803729a(15) =1940416a(16) =4684624a(17) =11309731a(18) =27304157a(19) =65918120a(20) =159140476a(21) =384199155a(22) =927538873a(23) =2239276992a(24) =5406092952a(25) =13051462995a(26) =31509019045a(27) =76069501192a(28) =183648021540a(29) =443365544387

External references