OFFSET
0,2
EXAMPLE
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.
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
Scott R. Shannon, Sep 26 2021
STATUS
approved