Triangle read by rows: numbers of nonintersecting circles with one of them marked.

Terms

a(0) =1a(1) =2a(2) =1a(3) =5a(4) =3a(5) =1a(6) =13a(7) =9a(8) =3a(9) =1a(10) =35a(11) =26a(12) =10a(13) =3a(14) =1a(15) =95a(16) =75a(17) =30a(18) =10a(19) =3a(20) =1a(21) =262a(22) =214a(23) =91a(24) =31a(25) =10a(26) =3a(27) =1a(28) =727a(29) =612