OFFSET
0,3
LINKS
R. Bacher, Table of n, a(n) for n = 0..24
R. Bacher, The special subgroup of invertible non-commutative rational power series as a metric group, arXiv:0804.1092
FORMULA
The reference contains a somewhat complicated formula.
EXAMPLE
The six polynomials corresponding to a(2) are: X, Y, X+Y, 1+X, 1+Y, 1+X+Y.
CROSSREFS
KEYWORD
nonn
AUTHOR
Roland Bacher, Apr 29 2008
STATUS
approved