a(n) is the number of almost almost unitary polyominoes of size n. An almost almost unitary polyomino is one in which all but 2 of its perimeter walls have length 1.
A362709
a(n) is the number of almost almost unitary polyominoes of size n. An almost almost unitary polyomino is one in which all but 2 of its perimeter walls have length 1.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =2a(4) =4a(5) =12a(6) =15a(7) =29a(8) =58a(9) =116a(10) =199a(11) =403a(12) =790a(13) =1509a(14) =2857a(15) =5700a(16) =10941a(17) =21032
External references
- oeis: A362709