%I #20 Jan 29 2023 04:46:15
%S 1,3,5,12,18,31,44,67,88,124,157,207,255,323,387,476,560,671,778,915,
%T 1046,1212,1371,1567,1757,1987,2209,2476,2734,3039,3336,3683,4020,
%U 4412,4793,5231,5659,6147,6623,7164,7692,8287,8870,9523,10162,10876,11575,12351
%N Number of isomorphism classes of nanocones with 3 pentagons and a symmetric boundary of length n.
%H Nico Van Cleemput, <a href="/A197988/b197988.txt">Table of n, a(n) for n = 1..75</a>
%H Gunnar Brinkmann and Nico Van Cleemput, <a href="https://doi.org/10.1016/j.dam.2011.06.014">Classification and generation of nanocones</a>, Discrete Applied Mathematics, 159 (2011), 1528-1539.
%F Conjectured g.f.: (x^7 + x^5 + x^4 + 2*x^3 + 2*x + 1)*x/((x - 1)^4*(x + 1)^2*(x^2 + x + 1)). [_D. S. McNeil_, Oct 20 2011]
%K nonn
%O 1,2
%A _Nico Van Cleemput_, Oct 20 2011