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%I #9 Dec 15 2015 07:26:43
%S 1,1,3,7,37,207,1470,11169,91166,776841,6865598,62443973
%N Number of nonisomorphic ways a loop can cross two parallel roads 2n times.
%C There is no obligation to cross the lower road (cf. A077054).
%Y Cf. A077054. Isomorphism classes from A085973.
%K nonn
%O 0,3
%A _N. J. A. Sloane_ and _Jon Wild_, Aug 25 2003
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