A013630 Irregular triangle read by rows, giving coefficients of polynomials arising as numerators of certain Hilbert series.

1, 1, 1, 1, 1, 8, 22, 8, 1, 1, 34, 295, 565, 295, 34, 1

Offset

2,6

Comments

The row 1,8,22,8,1 occurs on p. 78 of Ottaviani as the numerator for the Hilbert series of the invariant ring of eight ordered points in a projective space. - Tom Copeland, Feb 27 2020

Links

Table of n, a(n) for n=2..17.

G. Ottaviani, Five lectures on projective invariants, arXiv preprint arXiv:1305.2749 [math.AG], 2013.

D.-N. Verma, Towards Classifying Finite Point-Set Configurations, 1997, Unpublished. [Scanned copy of annotated version of preprint given to me by the author in 1997. - N. J. A. Sloane, Oct 04 2021]

Example

Triangle begins:
1,
1, 1, 1,
1, 8, 22, 8, 1,
1, 34, 295, 565, 295, 34, 1,
...

Crossrefs

Sequence in context: A019281 A284737 A323593 * A215600 A304301 A236917

Adjacent sequences: A013627 A013628 A013629 * A013631 A013632 A013633

Keyword

tabf,nonn,more

Author

N. J. A. Sloane

Status

approved