Number of connected unit interval graphs with n nodes; also number of bracelets (turnover necklaces) with n black beads and n-1 white beads.

A007123

Number of connected unit interval graphs with n nodes; also number of bracelets (turnover necklaces) with n black beads and n-1 white beads.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =26a(6) =76a(7) =232a(8) =750a(9) =2494a(10) =8524a(11) =29624a(12) =104468a(13) =372308a(14) =1338936a(15) =4850640a(16) =17685270a(17) =64834550a(18) =238843660a(19) =883677784a(20) =3282152588a(21) =12233309868a(22) =45741634536a(23) =171530482864a(24) =644953425740

External references