A060149 Number of homogeneous generators of degree n for graded algebra associated with meanders.

1, 3, 2, 13, 16, 106, 166, 1073, 1934, 12142, 24076, 147090, 312906, 1865772, 4191822, 24463905, 57433950, 328887346, 800740450, 4508608610, 11319707546, 62781858592, 161841539812, 885513974674, 2335765140994, 12624162072740, 33979681977530, 181611275997040

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Roland Bacher, Meander algebras

Formula

G.f.: 1 - 1/B(x) where B(x) is the g.f. of A018224. - Andrew Howroyd, Feb 07 2025

Prog

(PARI) seq(n) = Vec(1 - 1/sum(k=0, n, binomial(k, k\2)^2*x^k, O(x*x^n))) \\ Andrew Howroyd, Feb 07 2025

Crossrefs

Meander sequences in Bacher's paper: A005315, A060066, A060089, A060111, A060148, A060149, A060174, A060198, A060206.

Cf. A018224.

Sequence in context: A210604 A005352 A095131 * A376467 A059374 A098384

Adjacent sequences: A060146 A060147 A060148 * A060150 A060151 A060152

Keyword

nonn

Author

N. J. A. Sloane, Apr 10 2001

Extensions

a(11) onwards from Andrew Howroyd, Feb 07 2025

Status

approved