A331446 Irregular triangle read by rows: numbers of twisted cubics on Calabi-Yao hypersurfaces. Row n refers to hypersurfaces of degree n+1 in P^n, the entries in that row being indexed by partitions of n-4.

317206375, 6255156277440, 30528671745480104, 222548537108926490, 154090254047541417984, 2000750410187341381632, 12197109744970010814464, 897560654227562339370036, 17873898563070361396216980, 33815935806268253433549768, 174633921378662035929052320, 957208127608222375829677128

Offset

4,1

Links

Table of n, a(n) for n=4..15.

Geir Ellingsrud and Stein Arild Stromme, Bott's formula and enumerative geometry, J. Amer. Math. Soc. 9 (1996), 175-193; arXiv:alg-geom/9411005, 1994. See Th. 1.2.

Example

Triangle begins:
317206375,
6255156277440,
30528671745480104, 222548537108926490,
154090254047541417984, 2000750410187341381632, 12197109744970010814464,
897560654227562339370036, 17873898563070361396216980, 33815935806268253433549768, 174633921378662035929052320, 957208127608222375829677128,
...

Crossrefs

Cf. A331445.

Sequence in context: A105005 A157789 A331445 * A184573 A112429 A364265

Adjacent sequences: A331443 A331444 A331445 * A331447 A331448 A331449

Keyword

nonn,tabf

Author

N. J. A. Sloane, Jan 22 2020

Status

approved