cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A207851 Number of meanders of order 2n+1 (4*n+2 crossings of the infinite line) with only central 1-1 cut (no other 1-1 cuts).

Original entry on oeis.org

4, 16, 324, 12100, 595984, 35236096, 2363709924, 174221090404, 13815880848784, 1161868621405636, 102544273501721104, 9424551852935116804, 896612457556434503824, 87881363502264179831824, 8840846163309028336017124
Offset: 1

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Keywords

Comments

Central cut is a 1-1 cut at the center of the meander (the i-line is for i=n).

References

  • A. Panayotopoulos and P. Tsikouras, Properties of meanders, JCMCC 46 (2003), 181-190.
  • A. Panayotopoulos and P. Vlamos, Meandric Polygons, Ars Combinatoria 87 (2008), 147-159.

Crossrefs

A208357 Number of meanders of order 2n+1 (4*n+2 crossings of the infinite line) with central 1-1 cut.

Original entry on oeis.org

4, 64, 1764, 68644, 3341584, 190992400, 12310790116, 871343837764, 66469126179600, 5391179227622500, 460213149486493456, 41024422751464102500, 3795407861954983718544, 362631040029370613957184, 35638591665642822414493156, 3590789985613539065908070116, 369893506453438150061450367376
Offset: 1

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Author

Keywords

References

  • Antonios Panayotopoulos and Panos Tsikouras, Properties of meanders, JCMCC 46 (2003), 181-190.
  • Antonios Panayotopoulos and Panayiotis Vlamos, Meandric Polygons, Ars Combinatoria 87 (2008), 147-159.

Crossrefs

Formula

a(n) = A005315(n+1)^2.

Extensions

More terms using the data at A005315 added by Amiram Eldar, Jun 09 2024

A208358 Number of meanders of order n without 1-1 cuts.

Original entry on oeis.org

1, 2, 4, 18, 110, 772, 5936, 48618, 417398, 3716972, 34086194, 320225348, 3069943298, 29943487732, 296447910268, 2973356043818, 30166687749922, 309197338572932, 3198206243665998, 33353864893990660, 350443763627186256, 3707087785160487888, 39458245623693926384, 422389058260155207568
Offset: 1

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Author

Panayotis Vlamos, Feb 25 2012

Keywords

References

  • S. K. Lando and A. K. Zvonkin, Plane and projective meanders, Séries Formelles et Combinatoire Algebrique. Laboratoire Bordelais de Recherche Informatique, Universite Bordeaux I, 1991, pp. 287-303.

Crossrefs

Formula

a(n) = A005315(n) - A192927(n).
Showing 1-3 of 3 results.