A364712 - OEIS

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.

%I #18 Apr 11 2024 10:27:32

%S 13,10,36,25,80,37,100,56,109,71,176,85,158,105,200,102,226,102,241,

%T 178,253,150,312,176,269,149,336,224,395,192,309,216,381,207,592,230,

%U 336,239,497,312,481,266,405,348,526,270,549,317,497,277,570,354,532,334

%N 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.

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

%H Justus Springer, <a href="/A364712/b364712.txt">Table of n, a(n) for n = 1..200</a>

%H Daniel Haettig, Beatrice Hafner, Juergen Hausen and Justus Springer, <a href="https://arxiv.org/abs/2207.14790">Del Pezzo surfaces of Picard number one admitting a torus action</a>, arXiv:2207.14790 [math.AG], 2022.

%H Daniel Hättig, Jürgen Hausen, Justus Springer and Hendrik Süß, <a href="https://www.math.uni-tuebingen.de/forschung/algebra/ldp-database/">Log del Pezzo surfaces with torus action - a searchable database</a>

%Y Cf. A145582, A145581.

%K nonn

%O 1,1

%A _Justus Springer_, Aug 04 2023