A198015 Number of isomorphism classes of nanocones with 4 pentagons and a symmetric boundary of length n

1, 4, 16, 37, 89, 175, 336, 579, 975, 1533, 2363, 3477, 5030, 7040, 9716, 13078, 17400, 22707, 29342, 37336, 47112, 58705, 72627, 88918, 108185, 130476, 156502, 186315, 220741, 259839, 304554, 354953, 412111, 476101, 548137, 628299, 717946, 817168, 927478

Offset

2,2

Links

Nico Van Cleemput, Table of n, a(n) for n = 2..75

G. Brinkmann and N. Van Cleemput, Classification and generation of nanocones, Discrete Applied Mathematics, 159 (2011), 1528-1539.

Formula

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

Crossrefs

Sequence in context: A256322 A080855 A203299 * A103770 A121318 A152133

Adjacent sequences: A198012 A198013 A198014 * A198016 A198017 A198018

Keyword

nonn

Author

Nico Van Cleemput, Oct 20 2011

Status

approved