Number of symmetric (0,1)-matrices with exactly n entries equal to 1 and no zero rows or columns.

A135588

Number of symmetric (0,1)-matrices with exactly n entries equal to 1 and no zero rows or columns.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =20a(5) =74a(6) =302a(7) =1314a(8) =6122a(9) =29982a(10) =154718a(11) =831986a(12) =4667070a(13) =27118610a(14) =163264862a(15) =1013640242a(16) =6488705638a(17) =42687497378a(18) =288492113950

External references