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

Offset: 0

Author

N. J. A. Sloane, Mar 30 2013

Keywords

• nonn
• more

Comments

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

Links

• 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.