Number of 2-trees rooted at a triangle with two similar edges.

Terms

a(0) =1a(1) =2a(2) =2a(3) =7a(4) =11a(5) =25a(6) =43a(7) =106a(8) =180a(9) =453a(10) =797a(11) =2023a(12) =3632a(13) =9328a(14) =16960a(15) =44036a(16) =80989a(17) =211815a(18) =393098a(19) =1034958a(20) =1934813a(21) =5121356a(22) =9633260a(23) =25615432a(24) =48433926a(25) =129289382a(26) =245554773a(27) =657691061a(28) =1253974468a(29) =3368475942