A198016 Number of isomorphism classes of nanocones with 4 pentagons and a nearsymmetric boundary of length n.

2, 9, 32, 89, 204, 420, 786, 1376, 2272, 3589, 5450, 8021, 11474, 16032, 21928, 29452, 38902, 50645, 65056, 82585, 103692, 128920, 158822, 194044, 235240, 283165, 338586, 402377, 475422, 558724, 653296, 760276, 880814, 1016193, 1167708, 1336797, 1524908

Offset: 2

Author

Nico Van Cleemput, Oct 20 2011

Keywords

• nonn

Links

• Nico Van Cleemput, Table of n, a(n) for n = 2..75
• Gunnar Brinkmann and Nico Van Cleemput, Classification and generation of nanocones, Discrete Applied Mathematics, 159 (2011), 1528-1539.

Formula

Conjectured g.f.: x^2*(-2*x^8 + 5*x^7 + x^6 + 13*x^5 + 8*x^4 + 13*x^3 + 9*x^2 + 3*x + 2)/(x^12 - 3*x^11 + 2*x^10 + x^9 - x^8 + 2*x^7 - 4*x^6 + 2*x^5 - x^4 + x^3 + 2*x^2 - 3*x + 1). [D. S. McNeil, Oct 20 2011]