Nonisomorphic catafusenes with symmetry C_s.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =23a(6) =98a(7) =393a(8) =1600a(9) =6486a(10) =26694a(11) =110818a(12) =465890a(13) =1978032a(14) =8481860a(15) =36681383a(16) =159894915a(17) =701898184a(18) =3100972840a(19) =13779678410a(20) =61557361263a(21) =276326335318