A197988 - OEIS

A197988

Number of isomorphism classes of nanocones with 3 pentagons and a symmetric boundary of length n.

1, 3, 5, 12, 18, 31, 44, 67, 88, 124, 157, 207, 255, 323, 387, 476, 560, 671, 778, 915, 1046, 1212, 1371, 1567, 1757, 1987, 2209, 2476, 2734, 3039, 3336, 3683, 4020, 4412, 4793, 5231, 5659, 6147, 6623, 7164, 7692, 8287, 8870, 9523, 10162, 10876, 11575, 12351

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OFFSET

1,2

LINKS

Nico Van Cleemput, Table of n, a(n) for n = 1..75

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

FORMULA

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]

CROSSREFS

Sequence in context: A226652 A024696 A295360 * A025088 A279784 A198301

Adjacent sequences: A197985 A197986 A197987 * A197989 A197990 A197991

KEYWORD

nonn

AUTHOR

Nico Van Cleemput, Oct 20 2011

STATUS

approved