A348057 - OEIS

%I #9 Oct 06 2021 12:49:38

%S 1,4,10,28,74,202,534,1442,3822,10258,27202,72718,192840,514228,

%T 1363342,3629316,9619264,25575326,67765590,180001304,476807826,

%U 1265567600,3351529410,8890447682,23538665948,62409037914,165202281046

%N Number of n-step self-avoiding walks on three quadrants of a 2D square lattice.

%e a(2) = 10. Assuming the lower left quadrant is the one removed then a walk of left-down or down-left is not permitted, so the total number of 2-step walks is 4 * 3 - 2 = 10.

%Y Cf. A001411 (four quadrants), A116903 (two quadrants), A038373 (one quadrant), A129700 (half quadrant).

%K nonn,walk

%O 0,2

%A _Scott R. Shannon_, Sep 26 2021