Number of irredundant sets in the n X n rook complement graph.

Terms

a(0) =2a(1) =9a(2) =94a(3) =777a(4) =3286a(5) =10771a(6) =29366a(7) =69873a(8) =149950a(9) =297111a(10) =553114a(11) =980953a(12) =1677014a(13) =2793771a(14) =4584286a(15) =7492065a(16) =12335422a(17) =20688751a(18) =35673698a(19) =63602601a(20) =117391702a(21) =223644675a(22) =437338630a(23) =872239057a(24) =1763820926a(25) =3599298951a(26) =7386070186a(27) =15205369593a(28) =31353128470