OFFSET
1,2
COMMENTS
a(n) is the number of nodes at level n in certain generating tree, denoted C, that embeds the tree of numerical semigroups.
LINKS
Matthew House, Table of n, a(n) for n = 1..3328
Sergi Elizalde, Improved bounds on the number of numerical semigroups of a given genus, arXiv:0905.0489 [math.CO], May 4, 2009. See Table 1, p. 8.
PROG
(Maxima) gf : taylor(x*(2 - 3*x + x^2 - 4*x^3 + 3*x^4 - 2*x^5 + x*(1 - x - x^3)*sqrt((1 + 2*x)/(1 - 2*x)))/(2*(1 - 3*x + 3*x^2 - 3*x^3 + 4*x^4 - 3*x^5 + 2*x^6)), x, 0, 100)$
makelist(ratcoef(gf, x, n), n, 1, 100); /* Franck Maminirina Ramaharo, Jan 15 2019 */
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, May 06 2009
EXTENSIONS
Edited, and name replaced by the g.f. by Franck Maminirina Ramaharo, Jan 15 2019
STATUS
approved