This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A213451 N1209 #15 Aug 01 2021 17:15:11 %S A213451 3,15,69,309,1365,5973,25941,112065,482067,2066583,8834469,37677603, %T A213451 160367343 %N A213451 Number of fixed triangular strip polyedges with n edges. %D A213451 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %H A213451 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 A213451 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 A213451 Cf. A001334, A151540, A151541. %K A213451 nonn,more %O A213451 1,1 %A A213451 _N. J. A. Sloane_, Jun 11 2012 %E A213451 Better description and more terms from _Joseph Myers_, Jun 12 2012