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A046722 Number of semi-meanders of order n with 3 components. 2
1, 3, 11, 37, 126, 430, 1454, 4976, 16880, 57824, 197010, 675428, 2310268, 7927778, 27205180, 93448486, 321537086, 1105589516, 3812424912, 13121988240, 45330375774, 156172996170, 540314673678, 1863197292582, 6454265995454, 22275589419432, 77246945788890, 266813803179348 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 3..40

P. Di Francesco, O. Golinelli, and E. Guitter, Meander, folding and arch statistics, arXiv:hep-th/9506030, 1995.

P. Di Francesco, O. Golinelli, and E. Guitter, Meander, folding and arch statistics, Mathematical and Computer Modelling 26 (1997), 97-147.

CROSSREFS

Cf. A000682, A046726.

Sequence in context: A027064 A027066 A291415 * A214996 A180168 A232031

Adjacent sequences:  A046719 A046720 A046721 * A046723 A046724 A046725

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

a(15)-a(30) from Andrew Howroyd, Nov 27 2015

STATUS

approved

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Last modified December 14 15:01 EST 2019. Contains 329979 sequences. (Running on oeis4.)