A250098 Number of triangles in minimal triangulation of the orientable closed surface of genus n (S_n).

8, 14, 24, 20, 22, 24, 24, 26, 28, 28, 30, 30, 32, 32, 34, 34, 36, 36, 38, 38, 38, 40, 40, 42, 42, 42, 44, 44, 44, 46, 46, 46, 48, 48, 48, 48, 50, 50, 50, 52, 52, 52, 52, 54, 54, 54, 54, 56, 56, 56, 56, 58, 58, 58, 58, 60, 60, 60, 60, 62, 62

Offset

0,1

References

J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 742, Fact F19.

M. Jungerman and G. Ringel, Minimal triangulations on orientable surfaces, Acta Math. 145 (1980), 121-154.

Ringel, Gerhard. Wie man die geschlossenen nichtorientierbaren Flächen in möglichst wenig Dreiecke zerlegen kann. (German) Math. Ann. 130 (1955), 317--326. MR0075591 (17,774b)

Links

Table of n, a(n) for n=0..60.

Formula

a(n) = 2*ceiling((7 + sqrt(1+48*n))/2) + 4*(n-1), except a(2) = 24.

Crossrefs

See A123869 for number of vertices in a minimal triangulation.

Sequence in context: A325302 A053668 A218145 * A155156 A275898 A248427

Adjacent sequences: A250095 A250096 A250097 * A250099 A250100 A250101

Keyword

nonn

Author

N. J. A. Sloane, Nov 12 2014

Status

approved