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A067648
Number of knot diagrams of type 2PI with n crossings and two outgoing strings.
2
0, 2, 0, 2, 4, 12, 60, 226, 1076, 5156, 24984, 128548, 663040, 3514968, 18918792, 103123906, 569877652, 3180066004, 17921451960, 101842206548, 583109887600, 3361640932872, 19499226668816
OFFSET
0,2
CROSSREFS
Sequence in context: A274414 A079550 A226430 * A279327 A052438 A324045
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 05 2002
EXTENSIONS
Reference gives two further terms.
STATUS
approved