A364712 Number of families of non-toric log del Pezzo surfaces of Picard number one with Gorenstein index = n that admit an effective action of a one-dimensional torus.

13, 10, 36, 25, 80, 37, 100, 56, 109, 71, 176, 85, 158, 105, 200, 102, 226, 102, 241, 178, 253, 150, 312, 176, 269, 149, 336, 224, 395, 192, 309, 216, 381, 207, 592, 230, 336, 239, 497, 312, 481, 266, 405, 348, 526, 270, 549, 317, 497, 277, 570, 354, 532, 334

Offset: 1

Author

Justus Springer, Aug 04 2023

Keywords

• nonn

Comments

This sequence appears in Proposition 7.1, p. 27 of Haettig, Hafner, Hausen and Springer.

Links

• Justus Springer, Table of n, a(n) for n = 1..200
• Daniel Haettig, Beatrice Hafner, Juergen Hausen and Justus Springer, Del Pezzo surfaces of Picard number one admitting a torus action, arXiv:2207.14790 [math.AG], 2022.
• Daniel Hättig, Jürgen Hausen, Justus Springer and Hendrik Süß, Log del Pezzo surfaces with torus action - a searchable database

Crossrefs

Cf. A145582, A145581.