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A067647
Number of knot diagrams of type 1PI with n crossings and two outgoing strings.
2
0, 2, 4, 18, 108, 748, 5648, 45234, 378300, 3271204, 29049824, 263656356, 2436827328, 22871937208, 217536523260, 2092958991474, 20341256951692, 199471121367508, 1971730006936240, 19630246152650228
OFFSET
0,2
CROSSREFS
Sequence in context: A370524 A099938 A135069 * A208358 A213793 A287612
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 05 2002
EXTENSIONS
Reference gives two further terms.
STATUS
approved