cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

User: Vladimir Dotsenko

Vladimir Dotsenko's wiki page.

Vladimir Dotsenko has authored 3 sequences.

A382233 Dimensions of the homogeneous component of degree n of the free unital Jordan algebra on 3 generators.

Original entry on oeis.org

1, 3, 6, 18, 45, 135, 378, 1134, 3324, 9981, 29733, 89280, 267273
Offset: 0

Author

Vladimir Dotsenko, Mar 29 2025

Keywords

Comments

First few terms coincide with A032120 but A032120(8) = 3321. This corresponds to the fact that A032120 gives dimensions of components of the free special Jordan algebra (which follows from Cohn 1959), and 3324 - 3321 = 3 is the dimension of the GL_3-orbit of the so called Glennie identity.
The terms up to a(12) were computed using the Albert nonassociative algebra system.

Examples

			For n = 3, we have a(3)=18 since the following monomials form a basis: x(xx), x(xy), x(xz), x(yy), x(yz), x(zz), y(xx), y(xy), y(xz), y(yy), y(yz), y(zz), z(xx), z(xy), z(xz), z(yy), z(yz), z(zz), these are all commutative nonassociative monomials of degree 3, since the Jordan identity is of degree 4.
		

References

  • C. M. Glennie, Identities in Jordan algebras, pp. 307-313 of J. Leech, editor, Computational Problems in Abstract Algebra. Pergamon, Oxford, 1970.
  • D. P. Jacobs, The Albert nonassociative algebra system: a progress report, pp. 41-44 of Proceedings of the International Symposium on Symbolic and Algebraic Computation, Association for Computing Machinery, New York, NY, USA, 1994.

Crossrefs

A227250 Number of binary labeled trees with two-colored vertices that have n leaves and avoid the easiest to avoid 6-pattern set.

Original entry on oeis.org

1, 2, 6, 42, 390, 4698, 69174
Offset: 1

Author

Vladimir Dotsenko, Jul 04 2013

Keywords

Comments

There are two six-pattern sets that are the easiest to avoid, they are identified with one another by either swapping colors (black <-> white) or passing to complements (the latter implies that the compositional inverse e.g.f. F(x) of the sequence in question is -F(-x)). One of them is (in operation notation, with b/w encoding black/white vertices) {b(b(1,2),3), b(b(1,3),2), b(1,b(2,3)), b(w(1,3),2), b(1,w(2,3)), w(b(1,2),3)}, the other is {w(w(1,2),3), w(w(1,3),2), w(1,w(2,3)), w(b(1,3),2), w(1,b(2,3)), b(w(1,2),3)}.
Conjecture: E.g.f. (for offset 0) satisfies A'(x) = 1 + A(x)^3, with A(0)=1. The next terms are 1203498, 24163110, 549811962, 13982486166, 393026414922, ... - Vaclav Kotesovec, Jun 15 2015

References

  • V. Dotsenko, Pattern avoidance in labelled trees, Séminaire Lotharingien de Combinatoire, B67b (2012), 27 pp.

Crossrefs

A173990 Incorrect version of A007178.

Original entry on oeis.org

1, 1, 3, 13, 75, 530, 4449, 43236
Offset: 1

Author

Vladimir Dotsenko, Mar 04 2010

Keywords

Comments

Name was: Dimensions of components for the operad of level algebras.