21418970801
domain: N
Appears in sequences
- Number of n X n binary matrices containing no 2 X 2 all-1s sub-block.at n=6A139810
- Number of n X n binary matrices, symmetric under horizontal and vertical reflection, with no more than 3 ones in any 2 X 2 subblock.at n=11A141510
- Number of nX6 binary matrices with no 2X2 block having four 1's.at n=5A181249