Number of n X n symmetric binary matrices containing no more than one 1 in any 3 X 3 sub-block.
A139009
Number of n X n symmetric binary matrices containing no more than one 1 in any 3 X 3 sub-block.
Terms
- a(0) =1a(1) =2a(2) =3a(3) =4a(4) =10a(5) =29a(6) =73a(7) =255a(8) =1166a(9) =5371a(10) =29682a(11) =210876a(12) =1671283a(13) =15280803a(14) =171861787a(15) =2259744342a(16) =34374508575a(17) =625277335018
External references
- oeis: A139009