Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (9,n)-rectangular grid with k '1's and (9n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.
A228168
Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (9,n)-rectangular grid with k '1's and (9n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =20a(4) =44a(5) =66a(6) =66a(7) =44a(8) =20a(9) =5a(10) =1a(11) =1a(12) =5a(13) =45a(14) =208a(15) =792a(16) =2156a(17) =4704a(18) =7984a(19) =11034a(20) =12190a(21) =11034a(22) =7984a(23) =4704a(24) =2156a(25) =792a(26) =208a(27) =45a(28) =5a(29) =1
External references
- oeis: A228168