101856

Appears in sequences

• Number of n X 2 binary arrays indicating whether each 2 X 2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1) X 3 binary array with rows and columns of the latter in lexicographically nondecreasing order.at n=24A227085
• a(n) = A253086(2^n-1).at n=9A253087
• a(n) = sum of the 2^(n-1) even positive integers having bit length 2*n and in which, when written in binary, each run of 0's is of exactly the same length as the run of 1's immediately before it.at n=5A386705