OFFSET
1,1
MATHEMATICA
n = 10; t = Prepend[Nest[Flatten[Partition[#, 2] /. {{2, 2} -> {2, 2, 1, 1}, {2, 1} -> {2, 2, 1}, {1, 2} -> {2, 1, 1}, {1, 1} -> {2, 1}}] &, {2, 2}, n], 1]; t2 = Accumulate[t]; {t3, t4} = Transpose[Partition[t2, 2]]; Union[Intersection[t3, t4 + 1], Intersection[t3 + 1, t4]] (* T. D. Noe, Sep 26 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Sep 04 2012
STATUS
approved