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A213451 Number of fixed triangular strip polyedges with n edges.
(Formerly N1209)

%I N1209

%S 3,15,69,309,1365,5973,25941,112065,482067,2066583,8834469,37677603,

%T 160367343

%N Number of fixed triangular strip polyedges with n edges.

%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

%H C. Domb, <a href="http://dx.doi.org/10.1080/00018736000101199">On the theory of cooperative phenomena in crystals</a>, Advances in Phys., 9 (1960), 149-361. See page 354.

%F Apparently, a(n) = A001334(n)/2 for n >= 1. It needs to be clarified whether the objects described by this sequence are equivalent to the self-avoiding walks on the hexagonal lattice together with a restriction on their orientation. - _Hugo Pfoertner_, Jul 24 2021

%Y Cf. A001334, A151540, A151541.

%K nonn,more

%O 1,1

%A _N. J. A. Sloane_, Jun 11 2012

%E Better description and more terms from _Joseph Myers_, Jun 12 2012

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Last modified September 19 17:03 EDT 2021. Contains 347564 sequences. (Running on oeis4.)