The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #3 Mar 30 2012 16:49:18
%S 0,2,0,2,4,12,60,226,1076,5156,24984,128548,663040,3514968,18918792,
%T 103123906,569877652,3180066004,17921451960,101842206548,583109887600,
%U 3361640932872,19499226668816
%N Number of knot diagrams of type 2PI with n crossings and two outgoing strings.
%H J. L. Jacobsen and P. Zinn-Justin, <a href="http://arXiv.org/abs/math-ph/0102015">A Transfer Matrix approach to the Enumeration of Knots</a>
%Y Cf. A054993, A067647.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Feb 05 2002
%E Reference gives two further terms.