A223096 - OEIS

A223096

Number of symmetric meander shapes with 2n+1 crossings.

1, 1, 2, 5, 13, 36, 102, 299, 889, 2698, 8267, 25684, 80349, 253872, 806334, 2580279, 8290645, 26794566, 86881179, 283034120, 924521718, 3031535538, 9962795554

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

COMMENTS

Number of symmetric foldings of 2n+1 stamps (A007822) in which end leaves are outwards. [Stéphane Legendre, Apr 09 2013]

LINKS

Table of n, a(n) for n=0..22.

Stéphane Legendre, Illustration of initial terms

S. Legendre, Foldings and Meanders, arXiv preprint arXiv:1302.2025 [math.CO], 2013.

S. Legendre, Foldings and Meanders, Aust. J. Comb. 58(2), 275-291, 2014.

Index entries for sequences obtained by enumerating foldings

CROSSREFS

Cf. A007822, A077055.

Sequence in context: A116409 A279196 A002844 * A277996 A370168 A099164

Adjacent sequences: A223093 A223094 A223095 * A223097 A223098 A223099

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Mar 30 2013

STATUS

approved