A200919 Number of crossings on periodic braids with n strands such that all strands meet.

0, 0, 0, 1, 3, 5, 9, 13, 19, 25, 34

Offset

1,5

Links

Table of n, a(n) for n=1..11.

Duraid Madina, Illustration of initial terms a(1) .. a(7)

N. J. A. Sloane, Illustration for a(6) = 5

Crossrefs

Sequence in context: A209974 A099392 A080827 * A213207 A102378 A118026

Adjacent sequences: A200916 A200917 A200918 * A200920 A200921 A200922

Keyword

nonn,hard,nice,more

Author

Duraid Madina, Nov 24 2011

Extensions

a(11) added by Duraid Madina, Oct 03 2012

a(7) corrected by Duraid Madina, Dec 11 2012

Status

approved