Number of n X n symmetric binary arrays with rows, considered as binary numbers, in nondecreasing order, and no more than 2 1's in any row.

A162036

Number of n X n symmetric binary arrays with rows, considered as binary numbers, in nondecreasing order, and no more than 2 1's in any row.

Terms

    a(0) =2a(1) =5a(2) =12a(3) =28a(4) =71a(5) =186a(6) =507a(7) =1443a(8) =4241a(9) =12895a(10) =40333a(11) =129679a(12) =427455a(13) =1442384a(14) =4975291a(15) =17518890a(16) =62907021a(17) =230104503a(18) =856679290a(19) =3243467627a(20) =12479244341a(21) =48759284806a(22) =193353224018a(23) =777721210211

External references