Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in nondecreasing order, and no more than 2 ones in any row or column.

A162057

Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in nondecreasing order, and no more than 2 ones in any row or column.

Terms

    a(0) =2a(1) =6a(2) =13a(3) =34a(4) =86a(5) =233a(6) =652a(7) =1888a(8) =5683a(9) =17526a(10) =55868a(11) =182024a(12) =609103a(13) =2081152a(14) =7268823a(15) =25891230a(16) =93983793a(17) =347398900a(18) =1306005890a(19) =4991876362a(20) =19377811110a(21) =76372139937a(22) =305348766558

External references