Number of nX2 0,1 arrays with the row and column sums nondecreasing.

Terms

a(0) =3a(1) =8a(2) =17a(3) =37a(4) =73a(5) =151a(6) =293a(7) =598a(8) =1159a(9) =2358a(10) =4581a(11) =9314a(12) =18143a(13) =36880a(14) =72001a(15) =146325a(16) =286185a(17) =581427a(18) =1138813a(19) =2312865a(20) =4535493a(21) =9207989a(22) =18074789a(23) =36682275a(24) =72066977a(25) =146206411a(26) =287454709a(27) =582979035a(28) =1146938817a(29) =2325328271